[mono.git] / mcs / class / Managed.Windows.Forms / System.Windows.Forms / ListView.cs

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2004-2005 Novell, Inc. (http://www.novell.com)
//
// Authors:
//      Ravindra Kumar (rkumar@novell.com)
//      Jordi Mas i Hernandez, jordi@ximian.com
//      Mike Kestner (mkestner@novell.com)
//
// TODO:
//   - Feedback for item activation, change in cursor types as mouse moves.
//   - LabelEdit
//   - Drag and drop


// NOT COMPLETE


using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Globalization;

namespace System.Windows.Forms
{
        [DefaultEvent ("SelectedIndexChanged")]
        [DefaultProperty ("Items")]
        [Designer ("System.Windows.Forms.Design.ListViewDesigner, " + Consts.AssemblySystem_Design, "System.ComponentModel.Design.IDesigner")]
        public class ListView : Control
        {
                private ItemActivation activation = ItemActivation.Standard;
                private ListViewAlignment alignment = ListViewAlignment.Top;
                private bool allow_column_reorder = false;
                private bool auto_arrange = true;
                private bool check_boxes = false;
                private readonly CheckedIndexCollection checked_indices;
                private readonly CheckedListViewItemCollection checked_items;
                private readonly ColumnHeaderCollection columns;
                internal ListViewItem focused_item;
                private bool full_row_select = false;
                private bool grid_lines = false;
                private ColumnHeaderStyle header_style = ColumnHeaderStyle.Clickable;
                private bool hide_selection = true;
                private bool hover_selection = false;
                private IComparer item_sorter;
                private readonly ListViewItemCollection items;
                private bool label_edit = false;
                private bool label_wrap = true;
                private bool multiselect = true;
                private bool scrollable = true;
                private readonly SelectedIndexCollection selected_indices;
                private readonly SelectedListViewItemCollection selected_items;
                private SortOrder sort_order = SortOrder.None;
                private ImageList state_image_list;
                private bool updating = false;
                private View view = View.LargeIcon;
                private int layout_wd;    // We might draw more than our client area
                private int layout_ht;    // therefore we need to have these two.
                //private TextBox editor;   // Used for editing an item text
                HeaderControl header_control;
                internal ItemControl item_control;
                internal ScrollBar h_scroll; // used for scrolling horizontally
                internal ScrollBar v_scroll; // used for scrolling vertically
                internal int h_marker;          // Position markers for scrolling
                internal int v_marker;
                private int keysearch_tickcnt;
                private string keysearch_text;
                static private readonly int keysearch_keydelay = 1000;
                private int[] reordered_column_indices;

                // internal variables
                internal ImageList large_image_list;
                internal ImageList small_image_list;
                internal Size text_size = Size.Empty;

                #region Events
                public event LabelEditEventHandler AfterLabelEdit;

                [Browsable (false)]
                [EditorBrowsable (EditorBrowsableState.Never)]
                public new event EventHandler BackgroundImageChanged {
                        add { base.BackgroundImageChanged += value; }
                        remove { base.BackgroundImageChanged -= value; }
                }

                public event LabelEditEventHandler BeforeLabelEdit;
                public event ColumnClickEventHandler ColumnClick;
                public event EventHandler ItemActivate;
                public event ItemCheckEventHandler ItemCheck;
                public event ItemDragEventHandler ItemDrag;

                [Browsable (false)]
                [EditorBrowsable (EditorBrowsableState.Never)]
                public new event PaintEventHandler Paint {
                        add { base.Paint += value; }
                        remove { base.Paint -= value; }
                }

                public event EventHandler SelectedIndexChanged;

                [Browsable (false)]
                [EditorBrowsable (EditorBrowsableState.Never)]
                public new event EventHandler TextChanged {
                        add { base.TextChanged += value; }
                        remove { base.TextChanged -= value; }
                }

                #endregion // Events

                #region Public Constructors
                public ListView ()
                {
                        background_color = ThemeEngine.Current.ColorWindow;
                        items = new ListViewItemCollection (this);
                        checked_indices = new CheckedIndexCollection (this);
                        checked_items = new CheckedListViewItemCollection (this);
                        columns = new ColumnHeaderCollection (this);
                        foreground_color = SystemColors.WindowText;
                        selected_indices = new SelectedIndexCollection (this);
                        selected_items = new SelectedListViewItemCollection (this);

                        border_style = BorderStyle.Fixed3D;

                        header_control = new HeaderControl (this);
                        header_control.Visible = false;
                        Controls.AddImplicit (header_control);

                        item_control = new ItemControl (this);
                        Controls.AddImplicit (item_control);

                        h_scroll = new HScrollBar ();
                        Controls.AddImplicit (this.h_scroll);

                        v_scroll = new VScrollBar ();
                        Controls.AddImplicit (this.v_scroll);

                        h_marker = v_marker = 0;
                        keysearch_tickcnt = 0;

                        // scroll bars are disabled initially
                        h_scroll.Visible = false;
                        h_scroll.ValueChanged += new EventHandler(HorizontalScroller);
                        v_scroll.Visible = false;
                        v_scroll.ValueChanged += new EventHandler(VerticalScroller);

                        // event handlers
                        base.KeyDown += new KeyEventHandler(ListView_KeyDown);
                        SizeChanged += new EventHandler (ListView_SizeChanged);
                        GotFocus += new EventHandler (FocusChanged);
                        LostFocus += new EventHandler (FocusChanged);
                        MouseWheel += new MouseEventHandler(ListView_MouseWheel);

                        this.SetStyle (ControlStyles.UserPaint | ControlStyles.StandardClick, false);
                }
                #endregion      // Public Constructors

                #region Private Internal Properties
                internal Size CheckBoxSize {
                        get {
                                if (this.check_boxes) {
                                        if (this.state_image_list != null)
                                                return this.state_image_list.ImageSize;
                                        else
                                                return ThemeEngine.Current.ListViewCheckBoxSize;
                                }
                                return Size.Empty;
                        }
                }

                #endregion      // Private Internal Properties

                #region  Protected Properties
                protected override CreateParams CreateParams {
                        get { return base.CreateParams; }
                }

                protected override Size DefaultSize {
                        get { return ThemeEngine.Current.ListViewDefaultSize; }
                }
                #endregion      // Protected Properties

                #region Public Instance Properties
                [DefaultValue (ItemActivation.Standard)]
                public ItemActivation Activation {
                        get { return activation; }
                        set { 
                                if (value != ItemActivation.Standard && value != ItemActivation.OneClick && 
                                        value != ItemActivation.TwoClick) {
                                        throw new InvalidEnumArgumentException (string.Format
                                                ("Enum argument value '{0}' is not valid for Activation", value));
                                }
                                  
                                activation = value;
                        }
                }

                [DefaultValue (ListViewAlignment.Top)]
                [Localizable (true)]
                public ListViewAlignment Alignment {
                        get { return alignment; }
                        set {
                                if (value != ListViewAlignment.Default && value != ListViewAlignment.Left && 
                                        value != ListViewAlignment.SnapToGrid && value != ListViewAlignment.Top) {
                                        throw new InvalidEnumArgumentException (string.Format 
                                                ("Enum argument value '{0}' is not valid for Alignment", value));
                                }
                                
                                if (this.alignment != value) {
                                        alignment = value;
                                        // alignment does not matter in Details/List views
                                        if (this.view == View.LargeIcon ||
                                            this.View == View.SmallIcon)
                                                this.Redraw (true);
                                }
                        }
                }

                [DefaultValue (false)]
                public bool AllowColumnReorder {
                        get { return allow_column_reorder; }
                        set { allow_column_reorder = value; }
                }

                [DefaultValue (true)]
                public bool AutoArrange {
                        get { return auto_arrange; }
                        set {
                                if (auto_arrange != value) {
                                        auto_arrange = value;
                                        // autoarrange does not matter in Details/List views
                                        if (this.view == View.LargeIcon || this.View == View.SmallIcon)
                                                this.Redraw (true);
                                }
                        }
                }

                public override Color BackColor {
                        get {
                                if (background_color.IsEmpty)
                                        return ThemeEngine.Current.ColorWindow;
                                else
                                        return background_color;
                        }
                        set { background_color = value; }
                }

                [Browsable (false)]
                [EditorBrowsable (EditorBrowsableState.Never)]
                public override Image BackgroundImage {
                        get { return background_image; }
                        set {
                                if (value == background_image)
                                        return;

                                background_image = value;
                                OnBackgroundImageChanged (EventArgs.Empty);
                        }
                }

                [DefaultValue (BorderStyle.Fixed3D)]
                [DispId (-504)]
                public BorderStyle BorderStyle {
                        get { return InternalBorderStyle; }
                        set { InternalBorderStyle = value; }
                }

                [DefaultValue (false)]
                public bool CheckBoxes {
                        get { return check_boxes; }
                        set {
                                if (check_boxes != value) {
#if NET_2_0
                                        if (value && View == View.Tile)
                                                throw new NotSupportedException ("CheckBoxes are not"
                                                        + " supported in Tile view. Choose a different"
                                                        + " view or set CheckBoxes to false.");
#endif

                                        check_boxes = value;
                                        this.Redraw (true);
                                }
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public CheckedIndexCollection CheckedIndices {
                        get { return checked_indices; }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public CheckedListViewItemCollection CheckedItems {
                        get { return checked_items; }
                }

                [DesignerSerializationVisibility (DesignerSerializationVisibility.Content)]
                [Localizable (true)]
                [MergableProperty (false)]
                public ColumnHeaderCollection Columns {
                        get { return columns; }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public ListViewItem FocusedItem {
                        get {
                                return focused_item;
                        }
                }

                public override Color ForeColor {
                        get {
                                if (foreground_color.IsEmpty)
                                        return ThemeEngine.Current.ColorWindowText;
                                else
                                        return foreground_color;
                        }
                        set { foreground_color = value; }
                }

                [DefaultValue (false)]
                public bool FullRowSelect {
                        get { return full_row_select; }
                        set { full_row_select = value; }
                }

                [DefaultValue (false)]
                public bool GridLines {
                        get { return grid_lines; }
                        set {
                                if (grid_lines != value) {
                                        grid_lines = value;
                                        this.Redraw (false);
                                }
                        }
                }

                [DefaultValue (ColumnHeaderStyle.Clickable)]
                public ColumnHeaderStyle HeaderStyle {
                        get { return header_style; }
                        set {
                                if (header_style == value)
                                        return;

                                switch (value) {
                                case ColumnHeaderStyle.Clickable:
                                case ColumnHeaderStyle.Nonclickable:
                                case ColumnHeaderStyle.None:
                                        break;
                                default:
                                        throw new InvalidEnumArgumentException (string.Format 
                                                ("Enum argument value '{0}' is not valid for ColumnHeaderStyle", value));
                                }
                                
                                header_style = value;
                                if (view == View.Details)
                                        Redraw (true);
                        }
                }

                [DefaultValue (true)]
                public bool HideSelection {
                        get { return hide_selection; }
                        set {
                                if (hide_selection != value) {
                                        hide_selection = value;
                                        this.Redraw (false);
                                }
                        }
                }

                [DefaultValue (false)]
                public bool HoverSelection {
                        get { return hover_selection; }
                        set { hover_selection = value; }
                }

                [DesignerSerializationVisibility (DesignerSerializationVisibility.Content)]
                [Localizable (true)]
                [MergableProperty (false)]              
                public ListViewItemCollection Items {
                        get { return items; }
                }

                [DefaultValue (false)]
                public bool LabelEdit {
                        get { return label_edit; }
                        set { label_edit = value; }
                }

                [DefaultValue (true)]
                [Localizable (true)]
                public bool LabelWrap {
                        get { return label_wrap; }
                        set {
                                if (label_wrap != value) {
                                        label_wrap = value;
                                        this.Redraw (true);
                                }
                        }
                }

                [DefaultValue (null)]
                public ImageList LargeImageList {
                        get { return large_image_list; }
                        set {
                                large_image_list = value;
                                this.Redraw (true);
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public IComparer ListViewItemSorter {
                        get {
                                if (View != View.SmallIcon && View != View.LargeIcon && item_sorter is ItemComparer)
                                        return null;
                                return item_sorter;
                        }
                        set {
                                if (item_sorter != value) {
                                        item_sorter = value;
                                        Sort ();
                                }
                        }
                }

                [DefaultValue (true)]
                public bool MultiSelect {
                        get { return multiselect; }
                        set { multiselect = value; }
                }

                [DefaultValue (true)]
                public bool Scrollable {
                        get { return scrollable; }
                        set {
                                if (scrollable != value) {
                                        scrollable = value;
                                        this.Redraw (true);
                                }
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public SelectedIndexCollection SelectedIndices {
                        get { return selected_indices; }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public SelectedListViewItemCollection SelectedItems {
                        get { return selected_items; }
                }

#if NET_2_0
                [MonoTODO("Implement")]
                public bool ShowGroups {
                        get {
                                return false;
                        }

                        set {
                        }
                }
#endif

                [DefaultValue (null)]
                public ImageList SmallImageList {
                        get { return small_image_list; }
                        set {
                                small_image_list = value;
                                this.Redraw (true);
                        }
                }

                [DefaultValue (SortOrder.None)]
                public SortOrder Sorting {
                        get { return sort_order; }
                        set { 
                                if (!Enum.IsDefined (typeof (SortOrder), value)) {
                                        throw new InvalidEnumArgumentException ("value", (int) value,
                                                typeof (SortOrder));
                                }
                                
                                if (sort_order == value)
                                        return;

                                sort_order = value;

                                if (value == SortOrder.None) {
                                        if (item_sorter != null) {
                                                // ListViewItemSorter should never be reset for SmallIcon
                                                // and LargeIcon view
                                                if (View != View.SmallIcon && View != View.LargeIcon)
#if NET_2_0
                                                        item_sorter = null;
#else
                                                        // in .NET 1.1, only internal IComparer would be
                                                        // set to null
                                                        if (item_sorter is ItemComparer)
                                                                item_sorter = null;
#endif
                                        }
                                        this.Redraw (false);
                                } else {
                                        if (item_sorter == null)
                                                item_sorter = new ItemComparer (value);
                                        if (item_sorter is ItemComparer) {
#if NET_2_0
                                                item_sorter = new ItemComparer (value);
#else
                                                // in .NET 1.1, the sort order is not updated for
                                                // SmallIcon and LargeIcon views if no custom IComparer
                                                // is set
                                                if (View != View.SmallIcon && View != View.LargeIcon)
                                                        item_sorter = new ItemComparer (value);
#endif
                                        }
                                        Sort ();
                                }
                        }
                }

                [DefaultValue (null)]
                public ImageList StateImageList {
                        get { return state_image_list; }
                        set {
                                state_image_list = value;
                                this.Redraw (true);
                        }
                }

                [Bindable (false)]
                [Browsable (false)]
                [EditorBrowsable (EditorBrowsableState.Never)]
                public override string Text {
                        get { return text; } 
                        set {
                                if (value == text)
                                        return;

                                text = value;
                                this.Redraw (true);

                                OnTextChanged (EventArgs.Empty);
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public ListViewItem TopItem {
                        get {
                                // there is no item
                                if (this.items.Count == 0)
                                        return null;
                                // if contents are not scrolled
                                // it is the first item
                                else if (h_marker == 0 && v_marker == 0)
                                        return this.items [0];
                                // do a hit test for the scrolled position
                                else {
                                        foreach (ListViewItem item in this.items) {
                                                if (item.Bounds.X >= 0 && item.Bounds.Y >= 0)
                                                        return item;
                                        }
                                        return null;
                                }
                        }
                }

#if NET_2_0
                [MonoTODO("Implement")]
                public bool UseCompatibleStateImageBehavior {
                        get {
                                return false;
                        }

                        set {
                        }
                }
#endif

                [DefaultValue (View.LargeIcon)]
                public View View {
                        get { return view; }
                        set { 
                                if (!Enum.IsDefined (typeof (View), value))
                                        throw new InvalidEnumArgumentException ("value", (int) value,
                                                typeof (View));

                                if (view != value) {
#if NET_2_0
                                        if (CheckBoxes && value == View.Tile)
                                                throw new NotSupportedException ("CheckBoxes are not"
                                                        + " supported in Tile view. Choose a different"
                                                        + " view or set CheckBoxes to false.");
#endif

                                        h_scroll.Value = v_scroll.Value = 0;
                                        view = value; 
                                        Redraw (true);
                                }
                        }
                }
                #endregion      // Public Instance Properties

                #region Internal Methods Properties
                
                internal int FirstVisibleIndex {
                        get {
                                // there is no item
                                if (this.items.Count == 0)
                                        return 0;
                                                                        
                                if (h_marker == 0 && v_marker == 0)
                                        return 0;                                       
                                
                                foreach (ListViewItem item in this.items) {
                                        if (item.Bounds.Right >= 0 && item.Bounds.Bottom >= 0)
                                                return item.Index;
                                }
                                return 0;

                        }
                }

                
                internal int LastVisibleIndex {                 
                        get {                                                   
                                for (int i = FirstVisibleIndex; i < Items.Count; i++) {
                                        if (View == View.List || Alignment == ListViewAlignment.Left) {
                                                if (Items[i].Bounds.X > ClientRectangle.Right)
                                                        return i - 1;                                   
                                        } else {
                                                if (Items[i].Bounds.Y > ClientRectangle.Bottom)
                                                        return i - 1;                                   
                                        }
                                }
                                
                                return Items.Count - 1;
                        }
                }
                
                internal int TotalWidth {
                        get { return Math.Max (this.Width, this.layout_wd); }
                }

                internal int TotalHeight {
                        get { return Math.Max (this.Height, this.layout_ht); }
                }

                internal void Redraw (bool recalculate)
                {
                        // Avoid calculations when control is being updated
                        if (this.updating)
                                return;

                        if (recalculate)
                                CalculateListView (this.alignment);

                        Refresh ();
                }

                internal Size GetChildColumnSize (int index)
                {
                        Size ret_size = Size.Empty;
                        ColumnHeader col = this.columns [index];

                        if (col.Width == -2) { // autosize = max(items, columnheader)
                                Size size = Size.Ceiling (this.DeviceContext.MeasureString
                                                          (col.Text, this.Font));
                                ret_size = BiggestItem (index);
                                if (size.Width > ret_size.Width)
                                        ret_size = size;
                        }
                        else { // -1 and all the values < -2 are put under one category
                                ret_size = BiggestItem (index);
                                // fall back to empty columns' width if no subitem is available for a column
                                if (ret_size.IsEmpty) {
                                        ret_size.Width = ThemeEngine.Current.ListViewEmptyColumnWidth;
                                        if (col.Text.Length > 0)
                                                ret_size.Height = Size.Ceiling (this.DeviceContext.MeasureString
                                                                                (col.Text, this.Font)).Height;
                                        else
                                                ret_size.Height = this.Font.Height;
                                }
                        }

                        // adjust the size for icon and checkbox for 0th column
                        if (index == 0) {
                                ret_size.Width += (this.CheckBoxSize.Width + 4);
                                if (this.small_image_list != null)
                                        ret_size.Width += this.small_image_list.ImageSize.Width;
                        }
                        return ret_size;
                }

                // Returns the size of biggest item text in a column.
                private Size BiggestItem (int col)
                {
                        Size temp = Size.Empty;
                        Size ret_size = Size.Empty;

                        // 0th column holds the item text, we check the size of
                        // the various subitems falling in that column and get
                        // the biggest one's size.
                        foreach (ListViewItem item in items) {
                                if (col >= item.SubItems.Count)
                                        continue;

                                temp = Size.Ceiling (this.DeviceContext.MeasureString
                                                     (item.SubItems [col].Text, this.Font));
                                if (temp.Width > ret_size.Width)
                                        ret_size = temp;
                        }

                        // adjustment for space
                        if (!ret_size.IsEmpty)
                                ret_size.Width += 4;

                        return ret_size;
                }

                const int max_wrap_padding = 38;

                // Sets the size of the biggest item text as per the view
                private void CalcTextSize ()
                {                       
                        // clear the old value
                        text_size = Size.Empty;

                        if (items.Count == 0)
                                return;

                        text_size = BiggestItem (0);

                        if (view == View.LargeIcon && this.label_wrap) {
                                Size temp = Size.Empty;
                                if (this.check_boxes)
                                        temp.Width += 2 * this.CheckBoxSize.Width;
                                int icon_w = LargeImageList == null ? 12 : LargeImageList.ImageSize.Width;
                                temp.Width += icon_w + max_wrap_padding;
                                // wrapping is done for two lines only
                                if (text_size.Width > temp.Width) {
                                        text_size.Width = temp.Width;
                                        text_size.Height *= 2;
                                }
                        }
                        else if (view == View.List) {
                                // in list view max text shown in determined by the
                                // control width, even if scolling is enabled.
                                int max_wd = this.Width - (this.CheckBoxSize.Width - 2);
                                if (this.small_image_list != null)
                                        max_wd -= this.small_image_list.ImageSize.Width;

                                if (text_size.Width > max_wd)
                                        text_size.Width = max_wd;
                        }

                        // we do the default settings, if we have got 0's
                        if (text_size.Height <= 0)
                                text_size.Height = this.Font.Height;
                        if (text_size.Width <= 0)
                                text_size.Width = this.Width;

                        // little adjustment
                        text_size.Width += 4;
                        text_size.Height += 2;
                }

                private void Scroll (ScrollBar scrollbar, int delta)
                {
                        if (delta == 0 || !scrollbar.Visible)
                                return;

                        int max;
                        if (scrollbar == h_scroll)
                                max = h_scroll.Maximum - item_control.Width;
                        else
                                max = v_scroll.Maximum - item_control.Height;

                        int val = scrollbar.Value + delta;
                        if (val > max)
                                val = max;
                        else if (val < scrollbar.Minimum)
                                val = scrollbar.Minimum;
                        scrollbar.Value = val;
                }

                private void CalculateScrollBars ()
                {
                        Rectangle client_area = ClientRectangle;
                        
                        if (!this.scrollable || this.items.Count <= 0) {
                                h_scroll.Visible = false;
                                v_scroll.Visible = false;
                                item_control.Location = new Point (0, header_control.Height);
                                item_control.Height = ClientRectangle.Width - header_control.Height;
                                item_control.Width = ClientRectangle.Width;
                                header_control.Width = ClientRectangle.Width;
                                return;
                        }

                        // Don't calculate if the view is not displayable
                        if (client_area.Height < 0 || client_area.Width < 0)
                                return;

                        // making a scroll bar visible might make
                        // other scroll bar visible                     
                        if (layout_wd > client_area.Right) {
                                h_scroll.Visible = true;
                                if ((layout_ht + h_scroll.Height) > client_area.Bottom)
                                        v_scroll.Visible = true;                                        
                                else
                                        v_scroll.Visible = false;
                        } else if (layout_ht > client_area.Bottom) {                            
                                v_scroll.Visible = true;
                                if ((layout_wd + v_scroll.Width) > client_area.Right)
                                        h_scroll.Visible = true;
                                else
                                        h_scroll.Visible = false;
                        } else {
                                h_scroll.Visible = false;
                                v_scroll.Visible = false;
                        }                       

                        item_control.Height = ClientRectangle.Height - header_control.Height;

                        if (h_scroll.is_visible) {
                                h_scroll.Location = new Point (client_area.X, client_area.Bottom - h_scroll.Height);
                                h_scroll.Minimum = 0;

                                // if v_scroll is visible, adjust the maximum of the
                                // h_scroll to account for the width of v_scroll
                                if (v_scroll.Visible) {
                                        h_scroll.Maximum = layout_wd + v_scroll.Width;
                                        h_scroll.Width = client_area.Width - v_scroll.Width;
                                }
                                else {
                                        h_scroll.Maximum = layout_wd;
                                        h_scroll.Width = client_area.Width;
                                }
   
                                h_scroll.LargeChange = client_area.Width;
                                h_scroll.SmallChange = Font.Height;
                                item_control.Height -= h_scroll.Height;
                        }

                        if (header_control.is_visible)
                                header_control.Width = ClientRectangle.Width;
                        item_control.Width = ClientRectangle.Width;

                        if (v_scroll.is_visible) {
                                v_scroll.Location = new Point (client_area.Right - v_scroll.Width, client_area.Y);
                                v_scroll.Minimum = 0;

                                // if h_scroll is visible, adjust the maximum of the
                                // v_scroll to account for the height of h_scroll
                                if (h_scroll.Visible) {
                                        v_scroll.Maximum = layout_ht + h_scroll.Height;
                                        v_scroll.Height = client_area.Height; // - h_scroll.Height already done 
                                } else {
                                        v_scroll.Maximum = layout_ht;
                                        v_scroll.Height = client_area.Height;
                                }

                                v_scroll.LargeChange = client_area.Height;
                                v_scroll.SmallChange = Font.Height;
                                if (header_control.Visible)
                                        header_control.Width -= v_scroll.Width;
                                item_control.Width -= v_scroll.Width;
                        }
                }
                
                ColumnHeader GetReorderedColumn (int index)
                {
                        if (reordered_column_indices == null)
                                return Columns [index];
                        else
                                return Columns [reordered_column_indices [index]];
                }

                void ReorderColumn (ColumnHeader col, int index)
                {
                        if (reordered_column_indices == null) {
                                reordered_column_indices = new int [Columns.Count];
                                for (int i = 0; i < Columns.Count; i++)
                                        reordered_column_indices [i] = i;
                        }

                        if (reordered_column_indices [index] == col.Index)
                                return;

                        int[] curr = reordered_column_indices;
                        int[] result = new int [Columns.Count];
                        int curr_idx = 0;
                        for (int i = 0; i < Columns.Count; i++) {
                                if (curr_idx < Columns.Count && curr [curr_idx] == col.Index)
                                        curr_idx++;

                                if (i == index)
                                        result [i] = col.Index;
                                else
                                        result [i] = curr [curr_idx++];
                        }

                        reordered_column_indices = result;
                        LayoutDetails ();
                        header_control.Invalidate ();
                        item_control.Invalidate ();
                }

                Size LargeIconItemSize {
                        get {
                                int image_w = LargeImageList == null ? 12 : LargeImageList.ImageSize.Width;
                                int image_h = LargeImageList == null ? 2 : LargeImageList.ImageSize.Height;
                                int w = CheckBoxSize.Width + 2 + Math.Max (text_size.Width, image_w);
                                int h = text_size.Height + 2 + Math.Max (CheckBoxSize.Height, image_h);
                                return new Size (w, h);
                        }
                }

                Size SmallIconItemSize {
                        get {
                                int image_w = SmallImageList == null ? 0 : SmallImageList.ImageSize.Width;
                                int image_h = SmallImageList == null ? 0 : SmallImageList.ImageSize.Height;
                                int w = text_size.Width + 2 + CheckBoxSize.Width + image_w;
                                int h = Math.Max (text_size.Height, Math.Max (CheckBoxSize.Height, image_h));
                                return new Size (w, h);
                        }
                }

                int rows;
                int cols;
                ListViewItem[,] item_matrix;

                void LayoutIcons (bool large_icons, bool left_aligned, int x_spacing, int y_spacing)
                {
                        header_control.Visible = false;
                        header_control.Size = Size.Empty;
                        item_control.Visible = true;
                        item_control.Location = Point.Empty;

                        if (items.Count == 0)
                                return;

                        Size sz = large_icons ? LargeIconItemSize : SmallIconItemSize;

                        Rectangle area = ClientRectangle;

                        if (left_aligned) {
                                rows = (int) Math.Floor ((double)(area.Height - h_scroll.Height + y_spacing) / (double)(sz.Height + y_spacing));
                                if (rows <= 0)
                                        rows = 1;
                                cols = (int) Math.Ceiling ((double)items.Count / (double)rows);
                        } else {
                                cols = (int) Math.Floor ((double)(area.Width - v_scroll.Width + x_spacing) / (double)(sz.Width + x_spacing));
                                if (cols <= 0)
                                        cols = 1;
                                rows = (int) Math.Ceiling ((double)items.Count / (double)cols);
                        }

                        layout_ht = rows * (sz.Height + y_spacing) - y_spacing;
                        layout_wd = cols * (sz.Width + x_spacing) - x_spacing;
                        item_matrix = new ListViewItem [rows, cols];
                        int row = 0;
                        int col = 0;
                        foreach (ListViewItem item in items) {
                                int x = col * (sz.Width + x_spacing);
                                int y = row * (sz.Height + y_spacing);
                                item.Location = new Point (x, y);
                                item.Layout ();
                                item.row = row;
                                item.col = col;
                                item_matrix [row, col] = item;
                                if (left_aligned) {
                                        if (++row == rows) {
                                                row = 0;
                                                col++;
                                        }
                                } else {
                                        if (++col == cols) {
                                                col = 0;
                                                row++;
                                        }
                                }
                        }

                        item_control.Size = new Size (layout_wd, layout_ht);
                }

                void LayoutHeader ()
                {
                        int x = 0;
                        for (int i = 0; i < Columns.Count; i++) {
                                ColumnHeader col = GetReorderedColumn (i);
                                col.X = x;
                                col.Y = 0;
                                col.CalcColumnHeader ();
                                x += col.Wd;
                        }

                        if (x < ClientRectangle.Width)
                                x = ClientRectangle.Width;

                        if (header_style == ColumnHeaderStyle.None) {
                                header_control.Visible = false;
                                header_control.Size = Size.Empty;
                        } else {
                                header_control.Width = x;
                                header_control.Height = columns [0].Ht;
                                header_control.Visible = true;
                        }
                }

                void LayoutDetails ()
                {
                        if (columns.Count == 0) {
                                header_control.Visible = false;
                                item_control.Visible = false;
                                return;
                        }

                        LayoutHeader ();

                        item_control.Visible = true;
                        item_control.Location = new Point (0, header_control.Height);

                        int y = 0; 
                        if (items.Count > 0) {
                                foreach (ListViewItem item in items) {
                                        item.Layout ();
                                        item.Location = new Point (0, y);
                                        y += item.Bounds.Height + 2;
                                }

                                // some space for bottom gridline
                                if (grid_lines)
                                        y += 2;
                        }

                        layout_wd = Math.Max (header_control.Width, item_control.Width);
                        layout_ht = y + header_control.Height;
                }

                private void CalculateListView (ListViewAlignment align)
                {
                        CalcTextSize ();

                        switch (view) {
                        case View.Details:
                                LayoutDetails ();
                                break;

                        case View.SmallIcon:
                                LayoutIcons (false, alignment == ListViewAlignment.Left, 4, 2);
                                break;

                        case View.LargeIcon:
                                LayoutIcons (true, alignment == ListViewAlignment.Left,
                                             ThemeEngine.Current.ListViewHorizontalSpacing,
                                             ThemeEngine.Current.ListViewVerticalSpacing);
                                break;

                        case View.List:
                                LayoutIcons (false, true, 4, 2);
                                break;
                        }

                        CalculateScrollBars ();
                }

                bool HaveModKeys {
                        get {
                                return (XplatUI.State.ModifierKeys & (Keys.Control | Keys.Shift)) != 0;
                        }
                }

                private bool KeySearchString (KeyEventArgs ke)
                {
                        int current_tickcnt = Environment.TickCount;
                        if (keysearch_tickcnt > 0 && current_tickcnt - keysearch_tickcnt > keysearch_keydelay) {
                                keysearch_text = string.Empty;
                        }
                        
                        keysearch_text += (char) ke.KeyData;
                        keysearch_tickcnt = current_tickcnt;

                        int start = FocusedItem == null ? 0 : FocusedItem.Index;
                        int i = start;
                        while (true) {
                                if (CultureInfo.CurrentCulture.CompareInfo.IsPrefix (Items[i].Text, keysearch_text,
                                        CompareOptions.IgnoreCase)) {
                                        SetFocusedItem (Items [i]);
                                        items [i].Selected = true;
                                        EnsureVisible (i);
                                        break;
                                }
                                i = (i + 1  < Items.Count) ? i+1 : 0;

                                if (i == start)
                                        break;
                        }
                        return true;
                }

                int GetAdjustedIndex (Keys key)
                {
                        int result = -1;

                        if (View == View.Details) {
                                if (key == Keys.Up)
                                        result = FocusedItem.Index - 1;
                                else if (key == Keys.Down) {
                                        result = FocusedItem.Index + 1;
                                        if (result == items.Count)
                                                result = -1;
                                }
                                return result;
                        }

                        int row = FocusedItem.row;
                        int col = FocusedItem.col;

                        switch (key) {
                        case Keys.Left:
                                if (col == 0)
                                        return -1;
                                return item_matrix [row, col - 1].Index;

                        case Keys.Right:
                                if (col == (cols - 1))
                                        return -1;
                                while (item_matrix [row, col + 1] == null)
                                       row--;   
                                return item_matrix [row, col + 1].Index;

                        case Keys.Up:
                                if (row == 0)
                                        return -1;
                                return item_matrix [row - 1, col].Index;

                        case Keys.Down:
                                if (row == (rows - 1) || row == Items.Count - 1)
                                        return -1;
                                while (item_matrix [row + 1, col] == null)
                                       col--;   
                                return item_matrix [row + 1, col].Index;

                        default:
                                return -1;
                        }
                }

                ListViewItem selection_start;

                private bool SelectItems (ArrayList sel_items)
                {
                        bool changed = false;
                        ArrayList curr_items = SelectedItems.List;
                        foreach (ListViewItem item in curr_items)
                                if (!sel_items.Contains (item)) {
                                        item.Selected = false;
                                        changed = true;
                                }
                        foreach (ListViewItem item in sel_items)
                                if (!item.Selected) {
                                        item.Selected = true;
                                        changed = true;
                                }
                        return changed;
                }

                private void UpdateMultiSelection (int index)
                {
                        bool shift_pressed = (XplatUI.State.ModifierKeys & Keys.Shift) != 0;
                        bool ctrl_pressed = (XplatUI.State.ModifierKeys & Keys.Control) != 0;
                        ListViewItem item = items [index];

                        if (shift_pressed && selection_start != null) {
                                ArrayList list = new ArrayList ();
                                int start = Math.Min (selection_start.Index, index);
                                int end = Math.Max (selection_start.Index, index);
                                if (View == View.Details) {
                                        for (int i = start; i <= end; i++)
                                                list.Add (items [i]);
                                } else {
                                        int left = Math.Min (items [start].col, items [end].col);
                                        int right = Math.Max (items [start].col, items [end].col);
                                        int top = Math.Min (items [start].row, items [end].row);
                                        int bottom = Math.Max (items [start].row, items [end].row);
                                        foreach (ListViewItem curr in items)
                                                if (curr.row >= top && curr.row <= bottom && 
                                                    curr.col >= left && curr.col <= right)
                                                        list.Add (curr);
                                }
                                if (SelectItems (list))
                                        OnSelectedIndexChanged (EventArgs.Empty);
                        } else  if (ctrl_pressed) {
                                item.Selected = !item.Selected;
                                selection_start = item;
                                OnSelectedIndexChanged (EventArgs.Empty);
                        } else {
                                SelectedItems.Clear ();
                                item.Selected = true;
                                selection_start = item;
                                OnSelectedIndexChanged (EventArgs.Empty);
                        }
                }

                internal override bool InternalPreProcessMessage (ref Message msg)
                {
                        if (msg.Msg == (int)Msg.WM_KEYDOWN) {
                                Keys key_data = (Keys)msg.WParam.ToInt32();
                                if (HandleNavKeys (key_data))
                                        return true;
                        } 
                        return base.InternalPreProcessMessage (ref msg);
                }

                bool HandleNavKeys (Keys key_data)
                {
                        if (Items.Count == 0 || !item_control.Visible)
                                return false;

                        if (FocusedItem == null)
                                SetFocusedItem (Items [0]);

                        switch (key_data) {
                        case Keys.End:
                                SelectIndex (Items.Count - 1);
                                break;

                        case Keys.Home:                 
                                SelectIndex (0);
                                break;

                        case Keys.Left:
                        case Keys.Right:
                        case Keys.Up:                           
                        case Keys.Down:
                                SelectIndex (GetAdjustedIndex (key_data));
                                break;

                        default:
                                return false;
                        }

                        return true;
                }

                void SelectIndex (int index)
                {
                        if (index == -1)
                                return;

                        if (MultiSelect)
                                UpdateMultiSelection (index);
                        else if (!items [index].Selected) {
                                items [index].Selected = true;
                                OnSelectedIndexChanged (EventArgs.Empty);
                        }

                        SetFocusedItem (items [index]);                         
                        EnsureVisible (index);
                }

                private void ListView_KeyDown (object sender, KeyEventArgs ke)
                {                       
                        if (ke.Handled || Items.Count == 0 || !item_control.Visible)
                                return;

                        ke.Handled = KeySearchString (ke);
                }

                internal class ItemControl : Control {

                        ListView owner;
                        ListViewItem clicked_item;
                        ListViewItem last_clicked_item;
                        bool hover_processed = false;
                        bool checking = false;
                        
                        ListViewLabelEditTextBox edit_text_box;
                        internal ListViewItem edit_item;
                        LabelEditEventArgs edit_args;

                        public ItemControl (ListView owner)
                        {
                                this.owner = owner;
                                DoubleClick += new EventHandler(ItemsDoubleClick);
                                MouseDown += new MouseEventHandler(ItemsMouseDown);
                                MouseMove += new MouseEventHandler(ItemsMouseMove);
                                MouseHover += new EventHandler(ItemsMouseHover);
                                MouseUp += new MouseEventHandler(ItemsMouseUp);
                        }

                        void ItemsDoubleClick (object sender, EventArgs e)
                        {
                                if (owner.activation == ItemActivation.Standard && owner.ItemActivate != null)
                                        owner.ItemActivate (this, e);
                        }

                        enum BoxSelect {
                                None,
                                Normal,
                                Shift,
                                Control
                        }

                        BoxSelect box_select_mode = BoxSelect.None;
                        ArrayList prev_selection;
                        Point box_select_start;

                        Rectangle box_select_rect;
                        internal Rectangle BoxSelectRectangle {
                                get { return box_select_rect; }
                                set {
                                        if (box_select_rect == value)
                                                return;

                                        InvalidateBoxSelectRect ();
                                        box_select_rect = value;
                                        InvalidateBoxSelectRect ();
                                }
                        }

                        void InvalidateBoxSelectRect ()
                        {
                                if (BoxSelectRectangle.Size.IsEmpty)
                                        return;

                                Rectangle edge = BoxSelectRectangle;
                                edge.X -= 1;
                                edge.Y -= 1;
                                edge.Width += 2;
                                edge.Height = 2;
                                Invalidate (edge);
                                edge.Y = BoxSelectRectangle.Bottom - 1;
                                Invalidate (edge);
                                edge.Y = BoxSelectRectangle.Y - 1;
                                edge.Width = 2;
                                edge.Height = BoxSelectRectangle.Height + 2;
                                Invalidate (edge);
                                edge.X = BoxSelectRectangle.Right - 1;
                                Invalidate (edge);
                        }

                        private Rectangle CalculateBoxSelectRectangle (Point pt)
                        {
                                int left = Math.Min (box_select_start.X, pt.X);
                                int right = Math.Max (box_select_start.X, pt.X);
                                int top = Math.Min (box_select_start.Y, pt.Y);
                                int bottom = Math.Max (box_select_start.Y, pt.Y);
                                return Rectangle.FromLTRB (left, top, right, bottom);
                        }

                        ArrayList BoxSelectedItems {
                                get {
                                        ArrayList result = new ArrayList ();
                                        foreach (ListViewItem item in owner.Items) {
                                                Rectangle r = item.Bounds;
                                                r.X += r.Width / 4;
                                                r.Y += r.Height / 4;
                                                r.Width /= 2;
                                                r.Height /= 2;
                                                if (BoxSelectRectangle.IntersectsWith (r))
                                                        result.Add (item);
                                        }
                                        return result;
                                }
                        }

                        private bool PerformBoxSelection (Point pt)
                        {
                                if (box_select_mode == BoxSelect.None)
                                        return false;

                                BoxSelectRectangle = CalculateBoxSelectRectangle (pt);
                                
                                ArrayList box_items = BoxSelectedItems;

                                ArrayList items;

                                switch (box_select_mode) {

                                case BoxSelect.Normal:
                                        items = box_items;
                                        break;

                                case BoxSelect.Control:
                                        items = new ArrayList ();
                                        foreach (ListViewItem item in prev_selection)
                                                if (!box_items.Contains (item))
                                                        items.Add (item);
                                        foreach (ListViewItem item in box_items)
                                                if (!prev_selection.Contains (item))
                                                        items.Add (item);
                                        break;

                                case BoxSelect.Shift:
                                        items = box_items;
                                        foreach (ListViewItem item in box_items)
                                                prev_selection.Remove (item);
                                        foreach (ListViewItem item in prev_selection)
                                                items.Add (item);
                                        break;

                                default:
                                        throw new Exception ("Unexpected Selection mode: " + box_select_mode);
                                }

                                SuspendLayout ();
                                owner.SelectItems (items);
                                ResumeLayout ();

                                return true;
                        }

                        private void ToggleCheckState (ListViewItem item)
                        {
                                CheckState curr_state = item.Checked ?  CheckState.Checked : CheckState.Unchecked;
                                item.Checked = !item.Checked;
                                CheckState new_state = item.Checked ?  CheckState.Checked : CheckState.Unchecked;

                                ItemCheckEventArgs ice = new ItemCheckEventArgs (item.Index, curr_state, new_state);
                                owner.OnItemCheck (ice);
                        }

                        private void ItemsMouseDown (object sender, MouseEventArgs me)
                        {
                                if (owner.items.Count == 0)
                                        return;

                                Point pt = new Point (me.X, me.Y);
                                foreach (ListViewItem item in owner.items) {
                                        if (me.Clicks == 1 && item.CheckRectReal.Contains (pt)) {
                                                checking = true;
                                                if (me.Clicks > 1)
                                                        return;
                                                ToggleCheckState (item);
                                                return;
                                        }

                                        if (owner.View == View.Details && !owner.FullRowSelect) {
                                                if (item.GetBounds (ItemBoundsPortion.Label).Contains (pt)) {
                                                        clicked_item = item;
                                                        break;
                                                }
                                        } else {
                                                if (item.Bounds.Contains (pt)) {
                                                        clicked_item = item;
                                                        break;
                                                }
                                        }
                                }


                                if (clicked_item != null) {
                                        owner.SetFocusedItem (clicked_item);
                                        bool changed = !clicked_item.Selected;
                                        if (owner.MultiSelect)
                                                owner.UpdateMultiSelection (clicked_item.Index);
                                        else
                                                clicked_item.Selected = true;
                                
                                        if (changed)
                                                owner.OnSelectedIndexChanged (EventArgs.Empty);

                                        // Raise double click if the item was clicked. On MS the
                                        // double click is only raised if you double click an item
                                        if (me.Clicks > 1) {
                                                owner.OnDoubleClick (EventArgs.Empty);
                                                if (owner.CheckBoxes)
                                                        ToggleCheckState (clicked_item);
                                        } else if (me.Clicks == 1) {
                                                owner.OnClick (EventArgs.Empty);
                                                if (owner.LabelEdit && !changed)
                                                        BeginEdit (clicked_item); // this is probably not the correct place to execute BeginEdit
                                        }
                                } else {
                                        if (owner.MultiSelect) {
                                                Keys mods = XplatUI.State.ModifierKeys;
                                                if ((mods & Keys.Shift) != 0)
                                                        box_select_mode = BoxSelect.Shift;
                                                else if ((mods & Keys.Control) != 0)
                                                        box_select_mode = BoxSelect.Control;
                                                else
                                                        box_select_mode = BoxSelect.Normal;
                                                box_select_start = pt; 
                                                prev_selection = owner.SelectedItems.List;
                                        } else if (owner.SelectedItems.Count > 0) {
                                                owner.SelectedItems.Clear ();
                                                owner.OnSelectedIndexChanged (EventArgs.Empty);
                                        }
                                }
                        }

                        private void ItemsMouseMove (object sender, MouseEventArgs me)
                        {
                                if (PerformBoxSelection (new Point (me.X, me.Y)))
                                        return;

                                if (owner.HoverSelection && hover_processed) {

                                        Point pt = PointToClient (Control.MousePosition);
                                        ListViewItem item = owner.GetItemAt (pt.X, pt.Y);
                                        if (item == null || item.Selected)
                                                return;

                                        hover_processed = false;
                                        XplatUI.ResetMouseHover (Handle);
                                }
                        }


                        private void ItemsMouseHover (object sender, EventArgs e)
                        {
                                if (Capture || !owner.HoverSelection)
                                        return;

                                hover_processed = true;
                                Point pt = PointToClient (Control.MousePosition);
                                ListViewItem item = owner.GetItemAt (pt.X, pt.Y);

                                if (item == null)
                                        return;

                                item.Selected = true;
                                owner.OnSelectedIndexChanged (new EventArgs ());
                        }

                        private void ItemsMouseUp (object sender, MouseEventArgs me)
                        {
                                Capture = false;
                                if (owner.Items.Count == 0)
                                        return;

                                Point pt = new Point (me.X, me.Y);

                                Rectangle rect = Rectangle.Empty;
                                if (clicked_item != null) {
                                        if (owner.view == View.Details && !owner.full_row_select)
                                                rect = clicked_item.GetBounds (ItemBoundsPortion.Label);
                                        else
                                                rect = clicked_item.Bounds;

                                        if (rect.Contains (pt)) {
                                                switch (owner.activation) {
                                                case ItemActivation.OneClick:
                                                        owner.OnItemActivate (EventArgs.Empty);
                                                        break;

                                                case ItemActivation.TwoClick:
                                                        if (last_clicked_item == clicked_item) {
                                                                owner.OnItemActivate (EventArgs.Empty);
                                                                last_clicked_item = null;
                                                        } else
                                                                last_clicked_item = clicked_item;
                                                        break;
                                                default:
                                                        // DoubleClick activation is handled in another handler
                                                        break;
                                                }
                                        }
                                } else if (!checking && owner.SelectedItems.Count > 0 && BoxSelectRectangle.Size.IsEmpty) {
                                        // Need this to clean up background clicks
                                        owner.SelectedItems.Clear ();
                                        owner.OnSelectedIndexChanged (EventArgs.Empty);
                                }

                                clicked_item = null;
                                box_select_start = Point.Empty;
                                BoxSelectRectangle = Rectangle.Empty;
                                prev_selection = null;
                                box_select_mode = BoxSelect.None;
                                checking = false;
                        }
                        
                        internal void LabelEditFinished (object sender, EventArgs e)
                        {
                                EndEdit (edit_item);
                        }
                        
                        internal void BeginEdit (ListViewItem item)
                        {
                                if (edit_item != null)
                                        EndEdit (edit_item);
                                
                                if (edit_text_box == null) {
                                        edit_text_box = new ListViewLabelEditTextBox ();
                                        edit_text_box.BorderStyle = BorderStyle.FixedSingle;
                                        edit_text_box.EditingFinished += new EventHandler (LabelEditFinished);
                                        edit_text_box.Visible = false;
                                        Controls.Add (edit_text_box);
                                }
                                
                                item.EnsureVisible();
                                
                                edit_text_box.Reset ();
                                
                                switch (owner.view) {
                                        case View.List:
                                        case View.SmallIcon:
                                        case View.Details:
                                                edit_text_box.TextAlign = HorizontalAlignment.Left;
                                                edit_text_box.Bounds = item.GetBounds (ItemBoundsPortion.Label);
                                                SizeF sizef = DeviceContext.MeasureString (item.Text, item.Font);
                                                edit_text_box.Width = (int)sizef.Width + 4;
                                                edit_text_box.MaxWidth = owner.ClientRectangle.Width - edit_text_box.Bounds.X;
                                                edit_text_box.WordWrap = false;
                                                edit_text_box.Multiline = false;
                                                break;
                                        case View.LargeIcon:
                                                edit_text_box.TextAlign = HorizontalAlignment.Center;
                                                edit_text_box.Bounds = item.GetBounds (ItemBoundsPortion.Label);
                                                sizef = DeviceContext.MeasureString (item.Text, item.Font);
                                                edit_text_box.Width = (int)sizef.Width + 4;
                                                edit_text_box.MaxWidth = item.GetBounds(ItemBoundsPortion.Entire).Width;
                                                edit_text_box.MaxHeight = owner.ClientRectangle.Height - edit_text_box.Bounds.Y;
                                                edit_text_box.WordWrap = true;
                                                edit_text_box.Multiline = true;
                                                break;
                                }
                                
                                edit_text_box.Text = item.Text;
                                edit_text_box.Font = item.Font;
                                edit_text_box.Visible = true;
                                edit_text_box.Focus ();
                                edit_text_box.SelectAll ();
                                
                                edit_args = new LabelEditEventArgs (owner.Items.IndexOf(edit_item));
                                owner.OnBeforeLabelEdit (edit_args);
                                
                                if (edit_args.CancelEdit)
                                        EndEdit (item);
                                
                                edit_item = item;
                        }
                        
                        internal void EndEdit (ListViewItem item)
                        {
                                if (edit_text_box != null && edit_text_box.Visible) {
                                        edit_text_box.Visible = false;
                                }
                                
                                if (edit_item != null && edit_item == item) {
                                        owner.OnAfterLabelEdit (edit_args);
                                        
                                        if (!edit_args.CancelEdit) {
                                                if (edit_args.Label != null)
                                                        edit_item.Text = edit_args.Label;
                                                else
                                                        edit_item.Text = edit_text_box.Text;
                                        }
                                        
                                }
                                
                                
                                edit_item = null;
                        }

                        internal override void OnPaintInternal (PaintEventArgs pe)
                        {
                                ThemeEngine.Current.DrawListViewItems (pe.Graphics, pe.ClipRectangle, owner);
                        }

                        internal override void OnGotFocusInternal (EventArgs e)
                        {
                                owner.Focus ();
                        }
                }
                
                internal class ListViewLabelEditTextBox : TextBox
                {
                        int max_width = -1;
                        int min_width = -1;
                        
                        int max_height = -1;
                        int min_height = -1;
                        
                        int old_number_lines = 1;
                        
                        SizeF text_size_one_char;
                        
                        public ListViewLabelEditTextBox ()
                        {
                                min_height = DefaultSize.Height;
                                text_size_one_char = DeviceContext.MeasureString ("B", Font);
                        }
                        
                        public int MaxWidth {
                                set {
                                        if (value < min_width)
                                                max_width = min_width;
                                        else
                                                max_width = value;
                                }
                        }
                        
                        public int MaxHeight {
                                set {
                                        if (value < min_height)
                                                max_height = min_height;
                                        else
                                                max_height = value;
                                }
                        }
                        
                        public new int Width {
                                get {
                                        return base.Width;
                                }
                                set {
                                        min_width = value;
                                        base.Width = value;
                                }
                        }
                        
                        public override Font Font {
                                get {
                                        return base.Font;
                                }
                                set {
                                        base.Font = value;
                                        text_size_one_char = DeviceContext.MeasureString ("B", Font);
                                }
                        }
                        
                        protected override void OnTextChanged (EventArgs e)
                        {
                                SizeF text_size = DeviceContext.MeasureString (Text, Font);
                                
                                int new_width = (int)text_size.Width + 8;
                                
                                if (!Multiline)
                                        ResizeTextBoxWidth (new_width);
                                else {
                                        if (Width != max_width)
                                                ResizeTextBoxWidth (new_width);
                                        
                                        int number_lines = Lines.Length;
                                        
                                        if (number_lines != old_number_lines) {
                                                int new_height = number_lines * (int)text_size_one_char.Height + 4;
                                                old_number_lines = number_lines;
                                                
                                                ResizeTextBoxHeight (new_height);
                                        }
                                }
                                
                                base.OnTextChanged (e);
                        }
                        
                        protected override bool IsInputKey (Keys key_data)
                        {
                                if ((key_data & Keys.Alt) == 0) {
                                        switch (key_data & Keys.KeyCode) {
                                                case Keys.Enter:
                                                        return true;
                                        }
                                }
                                return base.IsInputKey (key_data);
                        }
                        
                        protected override void OnKeyDown (KeyEventArgs e)
                        {
                                if (e.KeyCode == Keys.Return && Visible) {
                                        this.Visible = false;
                                        OnEditingFinished (e);
                                }
                        }
                        
                        protected override void OnLostFocus (EventArgs e)
                        {
                                if (Visible) {
                                        OnEditingFinished (e);
                                }
                        }
                        
                        protected void OnEditingFinished (EventArgs e)
                        {
                                if (EditingFinished != null)
                                        EditingFinished (this, EventArgs.Empty);
                        }
                        
                        private void ResizeTextBoxWidth (int new_width)
                        {
                                if (new_width > max_width)
                                        base.Width = max_width;
                                else 
                                if (new_width >= min_width)
                                        base.Width = new_width;
                                else
                                        base.Width = min_width;
                        }
                        
                        private void ResizeTextBoxHeight (int new_height)
                        {
                                if (new_height > max_height)
                                        base.Height = max_height;
                                else 
                                if (new_height >= min_height)
                                        base.Height = new_height;
                                else
                                        base.Height = min_height;
                        }
                        
                        public void Reset ()
                        {
                                max_width = -1;
                                min_width = -1;
                                
                                max_height = -1;
                                
                                old_number_lines = 1;
                                
                                Text = String.Empty;
                                
                                Size = DefaultSize;
                        }
                        
                        public event EventHandler EditingFinished;
                }

                internal override void OnPaintInternal (PaintEventArgs pe)
                {
                        if (updating)
                                return; 
                                
                        CalculateScrollBars ();
                }

                void FocusChanged (object o, EventArgs args)
                {
                        if (Items.Count == 0)
                                return;

                        if (FocusedItem == null)
                                SetFocusedItem (Items [0]);

                        item_control.Invalidate (FocusedItem.Bounds);
                }

                private void ListView_MouseWheel (object sender, MouseEventArgs me)
                {
                        if (Items.Count == 0)
                                return;

                        int lines = me.Delta / 120;

                        if (lines == 0)
                                return;

                        switch (View) {
                        case View.Details:
                        case View.SmallIcon:
                                Scroll (v_scroll, -Items [0].Bounds.Height * SystemInformation.MouseWheelScrollLines * lines);
                                break;
                        case View.LargeIcon:
                                Scroll (v_scroll, -(Items [0].Bounds.Height + ThemeEngine.Current.ListViewVerticalSpacing)  * lines);
                                break;
                        case View.List:
                                Scroll (h_scroll, -Items [0].Bounds.Width * lines);
                                break;
                        }
                }

                private void ListView_SizeChanged (object sender, EventArgs e)
                {
                        CalculateListView (alignment);
                }
                
                private void SetFocusedItem (ListViewItem item)
                {
                        if (focused_item != null)
                                focused_item.Focused = false;
                        
                        if (item != null)
                                item.Focused = true;
                                
                        focused_item = item;
                }

                private void HorizontalScroller (object sender, EventArgs e)
                {
                        item_control.EndEdit (item_control.edit_item);
                        
                        // Avoid unnecessary flickering, when button is
                        // kept pressed at the end
                        if (h_marker != h_scroll.Value) {
                                
                                int pixels =  h_marker - h_scroll.Value;
                                
                                h_marker = h_scroll.Value;
                                if (header_control.Visible)
                                        XplatUI.ScrollWindow (header_control.Handle, pixels, 0, false);

                                XplatUI.ScrollWindow (item_control.Handle, pixels, 0, false);
                        }
                }

                private void VerticalScroller (object sender, EventArgs e)
                {
                        item_control.EndEdit (item_control.edit_item);
                        
                        // Avoid unnecessary flickering, when button is
                        // kept pressed at the end
                        if (v_marker != v_scroll.Value) {
                                int pixels =  v_marker - v_scroll.Value;
                                Rectangle area = item_control.ClientRectangle;
                                v_marker = v_scroll.Value;
                                XplatUI.ScrollWindow (item_control.Handle, area, 0, pixels, false);
                        }
                }
                #endregion      // Internal Methods Properties

                #region Protected Methods
                protected override void CreateHandle ()
                {
                        base.CreateHandle ();
                }

                protected override void Dispose (bool disposing)
                {                       
                        if (disposing) {                        
                                h_scroll.Dispose ();
                                v_scroll.Dispose ();
                                
                                large_image_list = null;
                                small_image_list = null;
                                state_image_list = null;
                        }
                        
                        base.Dispose (disposing);
                }

                protected override bool IsInputKey (Keys keyData)
                {
                        switch (keyData) {
                        case Keys.Up:
                        case Keys.Down:
                        case Keys.PageUp:
                        case Keys.PageDown:
                        case Keys.Right:
                        case Keys.Left:
                        case Keys.End:
                        case Keys.Home:                         
                                return true;

                        default:
                                break;
                        }
                        
                        return base.IsInputKey (keyData);
                }

                protected virtual void OnAfterLabelEdit (LabelEditEventArgs e)
                {
                        if (AfterLabelEdit != null)
                                AfterLabelEdit (this, e);
                }

                protected virtual void OnBeforeLabelEdit (LabelEditEventArgs e)
                {
                        if (BeforeLabelEdit != null)
                                BeforeLabelEdit (this, e);
                }

                protected virtual void OnColumnClick (ColumnClickEventArgs e)
                {
                        if (ColumnClick != null)
                                ColumnClick (this, e);
                }

                protected override void OnEnabledChanged (EventArgs e)
                {
                        base.OnEnabledChanged (e);
                }

                protected override void OnFontChanged (EventArgs e)
                {
                        base.OnFontChanged (e);
                        Redraw (true);
                }

                protected override void OnHandleCreated (EventArgs e)
                {
                        base.OnHandleCreated (e);
                        Sort ();
                }

                protected override void OnHandleDestroyed (EventArgs e)
                {
                        base.OnHandleDestroyed (e);
                }

                protected virtual void OnItemActivate (EventArgs e)
                {
                        if (ItemActivate != null)
                                ItemActivate (this, e);
                }

                protected virtual void OnItemCheck (ItemCheckEventArgs ice)
                {
                        if (ItemCheck != null)
                                ItemCheck (this, ice);
                }

                protected virtual void OnItemDrag (ItemDragEventArgs e)
                {
                        if (ItemDrag != null)
                                ItemDrag (this, e);
                }

                protected virtual void OnSelectedIndexChanged (EventArgs e)
                {
                        if (SelectedIndexChanged != null)
                                SelectedIndexChanged (this, e);
                }

                protected override void OnSystemColorsChanged (EventArgs e)
                {
                        base.OnSystemColorsChanged (e);
                }

                protected void RealizeProperties ()
                {
                        // FIXME: TODO
                }

                protected void UpdateExtendedStyles ()
                {
                        // FIXME: TODO
                }

                protected override void WndProc (ref Message m)
                {
                        base.WndProc (ref m);
                }
                #endregion // Protected Methods

                #region Public Instance Methods
                public void ArrangeIcons ()
                {
                        ArrangeIcons (this.alignment);
                }

                public void ArrangeIcons (ListViewAlignment alignment)
                {
                        // Icons are arranged only if view is set to LargeIcon or SmallIcon
                        if (view == View.LargeIcon || view == View.SmallIcon) {
                                this.CalculateListView (alignment);
                                // we have done the calculations already
                                this.Redraw (false);
                        }
                }

                public void BeginUpdate ()
                {
                        // flag to avoid painting
                        updating = true;
                }

                public void Clear ()
                {
                        columns.Clear ();
                        items.Clear (); // Redraw (true) called here                    
                }

                public void EndUpdate ()
                {
                        // flag to avoid painting
                        updating = false;

                        // probably, now we need a redraw with recalculations
                        this.Redraw (true);
                }

                public void EnsureVisible (int index)
                {
                        if (index < 0 || index >= items.Count || scrollable == false)
                                return;

                        Rectangle view_rect = item_control.ClientRectangle;
                        Rectangle bounds = items [index].Bounds;

                        if (view_rect.Contains (bounds))
                                return;

                        if (bounds.Left < 0)
                                h_scroll.Value += bounds.Left;
                        else if (bounds.Right > view_rect.Right)
                                h_scroll.Value += (bounds.Right - view_rect.Right);

                        if (bounds.Top < 0)
                                v_scroll.Value += bounds.Top;
                        else if (bounds.Bottom > view_rect.Bottom)
                                v_scroll.Value += (bounds.Bottom - view_rect.Bottom);
                }
                
                public ListViewItem GetItemAt (int x, int y)
                {
                        foreach (ListViewItem item in items) {
                                if (item.Bounds.Contains (x, y))
                                        return item;
                        }
                        return null;
                }

                public Rectangle GetItemRect (int index)
                {
                        return GetItemRect (index, ItemBoundsPortion.Entire);
                }

                public Rectangle GetItemRect (int index, ItemBoundsPortion portion)
                {
                        if (index < 0 || index >= items.Count)
                                throw new IndexOutOfRangeException ("index");

                        return items [index].GetBounds (portion);
                }

                public void Sort ()
                {
                        Sort (true);
                }

                // we need this overload to reuse the logic for sorting, while allowing
                // redrawing to be done by caller or have it done by this method when
                // sorting is really performed
                //
                // ListViewItemCollection's Add and AddRange methods call this overload
                // with redraw set to false, as they take care of redrawing themselves
                // (they even want to redraw the listview if no sort is performed, as 
                // an item was added), while ListView.Sort () only wants to redraw if 
                // sorting was actually performed
                private void Sort (bool redraw)
                {
                        if (!IsHandleCreated || item_sorter == null) {
                                return;
                        }
                        
                        items.Sort (item_sorter);
                        if (redraw)
                                this.Redraw (true);
                }

                public override string ToString ()
                {
                        int count = this.Items.Count;

                        if (count == 0)
                                return string.Format ("System.Windows.Forms.ListView, Items.Count: 0");
                        else
                                return string.Format ("System.Windows.Forms.ListView, Items.Count: {0}, Items[0]: {1}", count, this.Items [0].ToString ());
                }
                #endregion      // Public Instance Methods


                #region Subclasses

                class HeaderControl : Control {

                        ListView owner;
                        bool column_resize_active = false;
                        ColumnHeader resize_column;
                        ColumnHeader clicked_column;
                        ColumnHeader drag_column;
                        int drag_x;
                        int drag_to_index = -1;

                        public HeaderControl (ListView owner)
                        {
                                this.owner = owner;
                                MouseDown += new MouseEventHandler (HeaderMouseDown);
                                MouseMove += new MouseEventHandler (HeaderMouseMove);
                                MouseUp += new MouseEventHandler (HeaderMouseUp);
                        }

                        private ColumnHeader ColumnAtX (int x)
                        {
                                Point pt = new Point (x, 0);
                                ColumnHeader result = null;
                                foreach (ColumnHeader col in owner.Columns) {
                                        if (col.Rect.Contains (pt)) {
                                                result = col;
                                                break;
                                        }
                                }
                                return result;
                        }

                        private int GetReorderedIndex (ColumnHeader col)
                        {
                                if (owner.reordered_column_indices == null)
                                        return col.Index;
                                else
                                        for (int i = 0; i < owner.Columns.Count; i++)
                                                if (owner.reordered_column_indices [i] == col.Index)
                                                        return i;
                                throw new Exception ("Column index missing from reordered array");
                        }

                        private void HeaderMouseDown (object sender, MouseEventArgs me)
                        {
                                if (resize_column != null) {
                                        column_resize_active = true;
                                        Capture = true;
                                        return;
                                }

                                clicked_column = ColumnAtX (me.X + owner.h_marker);

                                if (clicked_column != null) {
                                        Capture = true;
                                        if (owner.AllowColumnReorder) {
                                                drag_x = me.X;
                                                drag_column = (ColumnHeader) (clicked_column as ICloneable).Clone ();
                                                drag_column.column_rect = clicked_column.Rect;
                                                drag_to_index = GetReorderedIndex (clicked_column);
                                        }
                                        clicked_column.pressed = true;
                                        Rectangle bounds = clicked_column.Rect;
                                        bounds.X -= owner.h_marker;
                                        Invalidate (bounds);
                                        return;
                                }
                        }

                        private void HeaderMouseMove (object sender, MouseEventArgs me)
                        {
                                Point pt = new Point (me.X + owner.h_marker, me.Y);

                                if (column_resize_active)  {
                                        resize_column.Width = pt.X - resize_column.X;
                                        if (resize_column.Width < 0)
                                                resize_column.Width = 0;
                                        return;
                                }

                                resize_column = null;

                                if (clicked_column != null) {
                                        if (owner.AllowColumnReorder) {
                                                Rectangle r;

                                                r = drag_column.column_rect;
                                                r.X = clicked_column.Rect.X + me.X - drag_x;
                                                drag_column.column_rect = r;

                                                int x = me.X + owner.h_marker;
                                                ColumnHeader over = ColumnAtX (x);
                                                if (over == null)
                                                        drag_to_index = owner.Columns.Count;
                                                else if (x < over.X + over.Width / 2)
                                                        drag_to_index = GetReorderedIndex (over);
                                                else
                                                        drag_to_index = GetReorderedIndex (over) + 1;
                                                Invalidate ();
                                        } else {
                                                ColumnHeader over = ColumnAtX (me.X + owner.h_marker);
                                                bool pressed = clicked_column.pressed;
                                                clicked_column.pressed = over == clicked_column;
                                                if (clicked_column.pressed ^ pressed) {
                                                        Rectangle bounds = clicked_column.Rect;
                                                        bounds.X -= owner.h_marker;
                                                        Invalidate (bounds);
                                                }
                                        }
                                        return;
                                }

                                for (int i = 0; i < owner.Columns.Count; i++) {
                                        Rectangle zone = owner.Columns [i].Rect;
                                        zone.X = zone.Right - 5;
                                        zone.Width = 10;
                                        if (zone.Contains (pt)) {
                                                if (i < owner.Columns.Count - 1 && owner.Columns [i + 1].Width == 0)
                                                        i++;
                                                resize_column = owner.Columns [i];
                                                break;
                                        }
                                }

                                if (resize_column == null)
                                        Cursor = Cursors.Default;
                                else
                                        Cursor = Cursors.VSplit;
                        }

                        void HeaderMouseUp (object sender, MouseEventArgs me)
                        {
                                Capture = false;

                                if (column_resize_active) {
                                        column_resize_active = false;
                                        resize_column = null;
                                        Cursor = Cursors.Default;
                                        return;
                                }

                                if (clicked_column != null && clicked_column.pressed) {
                                        clicked_column.pressed = false;
                                        Rectangle bounds = clicked_column.Rect;
                                        bounds.X -= owner.h_marker;
                                        Invalidate (bounds);
                                        owner.OnColumnClick (new ColumnClickEventArgs (clicked_column.Index));
                                }

                                if (drag_column != null && owner.AllowColumnReorder) {
                                        drag_column = null;
                                        if (drag_to_index > GetReorderedIndex (clicked_column))
                                                drag_to_index--;
                                        if (owner.GetReorderedColumn (drag_to_index) != clicked_column)
                                                owner.ReorderColumn (clicked_column, drag_to_index);
                                        drag_to_index = -1;
                                        Invalidate ();
                                }

                                clicked_column = null;
                        }

                        internal override void OnPaintInternal (PaintEventArgs pe)
                        {
                                if (owner.updating)
                                        return; 
                                
                                Theme theme = ThemeEngine.Current;
                                theme.DrawListViewHeader (pe.Graphics, pe.ClipRectangle, this.owner);

                                if (drag_column == null)
                                        return;

                                int target_x;
                                if (drag_to_index == owner.Columns.Count)
                                        target_x = owner.GetReorderedColumn (drag_to_index - 1).Rect.Right - owner.h_marker;
                                else
                                        target_x = owner.GetReorderedColumn (drag_to_index).Rect.X - owner.h_marker;
                                theme.DrawListViewHeaderDragDetails (pe.Graphics, owner, drag_column, target_x);
                        }

                        protected override void WndProc (ref Message m)
                        {
                                switch ((Msg)m.Msg) {
                                case Msg.WM_SETFOCUS:
                                        owner.Focus ();
                                        break;
                                default:
                                        base.WndProc (ref m);
                                        break;
                                }
                        }
                }

                private class ItemComparer : IComparer {
                        readonly SortOrder sort_order;

                        public ItemComparer (SortOrder sortOrder)
                        {
                                sort_order = sortOrder;
                        }

                        public int Compare (object x, object y)
                        {
                                ListViewItem item_x = x as ListViewItem;
                                ListViewItem item_y = y as ListViewItem;
                                if (sort_order == SortOrder.Ascending)
                                        return String.Compare (item_x.Text, item_y.Text);
                                else
                                        return String.Compare (item_y.Text, item_x.Text);
                        }
                }

                public class CheckedIndexCollection : IList, ICollection, IEnumerable
                {
                        private readonly ListView owner;

                        #region Public Constructor
                        public CheckedIndexCollection (ListView owner)
                        {
                                this.owner = owner;
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get { return owner.CheckedItems.Count; }
                        }

                        public bool IsReadOnly {
                                get { return true; }
                        }

                        public int this [int index] {
                                get {
                                        int [] indices = GetIndices ();
                                        if (index < 0 || index >= indices.Length)
                                                throw new ArgumentOutOfRangeException ("index");
                                        return indices [index];
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return false; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return true; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set { throw new NotSupportedException ("SetItem operation is not supported."); }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public bool Contains (int checkedIndex)
                        {
                                int [] indices = GetIndices ();
                                for (int i = 0; i < indices.Length; i++) {
                                        if (indices [i] == checkedIndex)
                                                return true;
                                }
                                return false;
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                int [] indices = GetIndices ();
                                return indices.GetEnumerator ();
                        }

                        void ICollection.CopyTo (Array dest, int index)
                        {
                                int [] indices = GetIndices ();
                                Array.Copy (indices, 0, dest, index, indices.Length);
                        }

                        int IList.Add (object value)
                        {
                                throw new NotSupportedException ("Add operation is not supported.");
                        }

                        void IList.Clear ()
                        {
                                throw new NotSupportedException ("Clear operation is not supported.");
                        }

                        bool IList.Contains (object checkedIndex)
                        {
                                if (!(checkedIndex is int))
                                        return false;
                                return Contains ((int) checkedIndex);
                        }

                        int IList.IndexOf (object checkedIndex)
                        {
                                if (!(checkedIndex is int))
                                        return -1;
                                return IndexOf ((int) checkedIndex);
                        }

                        void IList.Insert (int index, object value)
                        {
                                throw new NotSupportedException ("Insert operation is not supported.");
                        }

                        void IList.Remove (object value)
                        {
                                throw new NotSupportedException ("Remove operation is not supported.");
                        }

                        void IList.RemoveAt (int index)
                        {
                                throw new NotSupportedException ("RemoveAt operation is not supported.");
                        }

                        public int IndexOf (int checkedIndex)
                        {
                                int [] indices = GetIndices ();
                                for (int i = 0; i < indices.Length; i++) {
                                        if (indices [i] == checkedIndex)
                                                return i;
                                }
                                return -1;
                        }
                        #endregion      // Public Methods

                        private int [] GetIndices ()
                        {
                                ArrayList checked_items = owner.CheckedItems.List;
                                int [] indices = new int [checked_items.Count];
                                for (int i = 0; i < checked_items.Count; i++) {
                                        ListViewItem item = (ListViewItem) checked_items [i];
                                        indices [i] = item.Index;
                                }
                                return indices;
                        }
                }       // CheckedIndexCollection

                public class CheckedListViewItemCollection : IList, ICollection, IEnumerable
                {
                        private readonly ListView owner;
                        private ArrayList list;

                        #region Public Constructor
                        public CheckedListViewItemCollection (ListView owner)
                        {
                                this.owner = owner;
                                this.owner.Items.Changed += new CollectionChangedHandler (
                                        ItemsCollection_Changed);
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get {
                                        if (!owner.CheckBoxes)
                                                return 0;
                                        return List.Count;
                                }
                        }

                        public bool IsReadOnly {
                                get { return true; }
                        }

                        public ListViewItem this [int index] {
                                get {
                                        ArrayList checked_items = List;
                                        if (index < 0 || index >= checked_items.Count)
                                                throw new ArgumentOutOfRangeException ("index");
                                        return (ListViewItem) checked_items [index];
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return false; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return true; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set { throw new NotSupportedException ("SetItem operation is not supported."); }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public bool Contains (ListViewItem item)
                        {
                                if (!owner.CheckBoxes)
                                        return false;
                                return List.Contains (item);
                        }

                        public void CopyTo (Array dest, int index)
                        {
                                if (!owner.CheckBoxes)
                                        return;
                                List.CopyTo (dest, index);
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                if (!owner.CheckBoxes)
                                        return (new ListViewItem [0]).GetEnumerator ();
                                return List.GetEnumerator ();
                        }

                        int IList.Add (object value)
                        {
                                throw new NotSupportedException ("Add operation is not supported.");
                        }

                        void IList.Clear ()
                        {
                                throw new NotSupportedException ("Clear operation is not supported.");
                        }

                        bool IList.Contains (object item)
                        {
                                if (!(item is ListViewItem))
                                        return false;
                                return Contains ((ListViewItem) item);
                        }

                        int IList.IndexOf (object item)
                        {
                                if (!(item is ListViewItem))
                                        return -1;
                                return IndexOf ((ListViewItem) item);
                        }

                        void IList.Insert (int index, object value)
                        {
                                throw new NotSupportedException ("Insert operation is not supported.");
                        }

                        void IList.Remove (object value)
                        {
                                throw new NotSupportedException ("Remove operation is not supported.");
                        }

                        void IList.RemoveAt (int index)
                        {
                                throw new NotSupportedException ("RemoveAt operation is not supported.");
                        }

                        public int IndexOf (ListViewItem item)
                        {
                                if (!owner.CheckBoxes)
                                        return -1;
                                return List.IndexOf (item);
                        }
                        #endregion      // Public Methods

                        internal ArrayList List {
                                get {
                                        if (list == null) {
                                                list = new ArrayList ();
                                                foreach (ListViewItem item in owner.Items) {
                                                        if (item.Checked)
                                                                list.Add (item);
                                                }
                                        }
                                        return list;
                                }
                        }

                        internal void Reset ()
                        {
                                // force re-population of list
                                list = null;
                        }

                        private void ItemsCollection_Changed ()
                        {
                                Reset ();
                        }
                }       // CheckedListViewItemCollection

                public class ColumnHeaderCollection : IList, ICollection, IEnumerable
                {
                        internal ArrayList list;
                        private ListView owner;

                        #region Public Constructor
                        public ColumnHeaderCollection (ListView owner)
                        {
                                list = new ArrayList ();
                                this.owner = owner;
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get { return list.Count; }
                        }

                        public bool IsReadOnly {
                                get { return false; }
                        }

                        public virtual ColumnHeader this [int index] {
                                get {
                                        if (index < 0 || index >= list.Count)
                                                throw new ArgumentOutOfRangeException ("index");
                                        return (ColumnHeader) list [index];
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return true; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return list.IsFixedSize; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set { throw new NotSupportedException ("SetItem operation is not supported."); }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public virtual int Add (ColumnHeader value)
                        {
                                int idx;
                                value.owner = this.owner;
                                idx = list.Add (value);
                                if (owner.IsHandleCreated) {
                                        owner.Redraw (true); 
                                }
                                return idx;
                        }

                        public virtual ColumnHeader Add (string str, int width, HorizontalAlignment textAlign)
                        {
                                ColumnHeader colHeader = new ColumnHeader (this.owner, str, textAlign, width);
                                this.Add (colHeader);                                                                   
                                return colHeader;
                        }

                        public virtual void AddRange (ColumnHeader [] values)
                        {
                                foreach (ColumnHeader colHeader in values) {
                                        colHeader.owner = this.owner;
                                        Add (colHeader);
                                }
                                
                                owner.Redraw (true); 
                        }

                        public virtual void Clear ()
                        {
                                list.Clear ();
                                owner.Redraw (true);
                        }

                        public bool Contains (ColumnHeader value)
                        {
                                return list.Contains (value);
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                return list.GetEnumerator ();
                        }

                        void ICollection.CopyTo (Array dest, int index)
                        {
                                list.CopyTo (dest, index);
                        }

                        int IList.Add (object value)
                        {
                                if (! (value is ColumnHeader)) {
                                        throw new ArgumentException ("Not of type ColumnHeader", "value");
                                }

                                return this.Add ((ColumnHeader) value);
                        }

                        bool IList.Contains (object value)
                        {
                                if (! (value is ColumnHeader)) {
                                        throw new ArgumentException ("Not of type ColumnHeader", "value");
                                }

                                return this.Contains ((ColumnHeader) value);
                        }

                        int IList.IndexOf (object value)
                        {
                                if (! (value is ColumnHeader)) {
                                        throw new ArgumentException ("Not of type ColumnHeader", "value");
                                }

                                return this.IndexOf ((ColumnHeader) value);
                        }

                        void IList.Insert (int index, object value)
                        {
                                if (! (value is ColumnHeader)) {
                                        throw new ArgumentException ("Not of type ColumnHeader", "value");
                                }

                                this.Insert (index, (ColumnHeader) value);
                        }

                        void IList.Remove (object value)
                        {
                                if (! (value is ColumnHeader)) {
                                        throw new ArgumentException ("Not of type ColumnHeader", "value");
                                }

                                this.Remove ((ColumnHeader) value);
                        }

                        public int IndexOf (ColumnHeader value)
                        {
                                return list.IndexOf (value);
                        }

                        public void Insert (int index, ColumnHeader value)
                        {
                                // LAMESPEC: MSDOCS say greater than or equal to the value of the Count property
                                // but it's really only greater.
                                if (index < 0 || index > list.Count)
                                        throw new ArgumentOutOfRangeException ("index");

                                value.owner = this.owner;
                                list.Insert (index, value);
                                owner.Redraw (true);
                        }

                        public void Insert (int index, string str, int width, HorizontalAlignment textAlign)
                        {
                                ColumnHeader colHeader = new ColumnHeader (this.owner, str, textAlign, width);
                                this.Insert (index, colHeader);
                        }

                        public virtual void Remove (ColumnHeader column)
                        {
                                // TODO: Update Column internal index ?
                                list.Remove (column);
                                owner.Redraw (true);
                        }

                        public virtual void RemoveAt (int index)
                        {
                                if (index < 0 || index >= list.Count)
                                        throw new ArgumentOutOfRangeException ("index");

                                // TODO: Update Column internal index ?
                                list.RemoveAt (index);
                                owner.Redraw (true);
                        }
                        #endregion      // Public Methods
                        

                }       // ColumnHeaderCollection

                public class ListViewItemCollection : IList, ICollection, IEnumerable
                {
                        private readonly ArrayList list;
                        private readonly ListView owner;

                        #region Public Constructor
                        public ListViewItemCollection (ListView owner)
                        {
                                list = new ArrayList ();
                                this.owner = owner;
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get { return list.Count; }
                        }

                        public bool IsReadOnly {
                                get { return false; }
                        }

                        public virtual ListViewItem this [int displayIndex] {
                                get {
                                        if (displayIndex < 0 || displayIndex >= list.Count)
                                                throw new ArgumentOutOfRangeException ("displayIndex");
                                        return (ListViewItem) list [displayIndex];
                                }

                                set {
                                        if (displayIndex < 0 || displayIndex >= list.Count)
                                                throw new ArgumentOutOfRangeException ("displayIndex");

                                        if (list.Contains (value))
                                                throw new ArgumentException ("An item cannot be added more than once. To add an item again, you need to clone it.", "value");

                                        value.Owner = owner;
                                        list [displayIndex] = value;
                                        OnChange ();

                                        owner.Redraw (true);
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return true; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return list.IsFixedSize; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set {
                                        if (value is ListViewItem)
                                                this [index] = (ListViewItem) value;
                                        else
                                                this [index] = new ListViewItem (value.ToString ());
                                        OnChange ();
                                }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public virtual ListViewItem Add (ListViewItem value)
                        {
                                if (list.Contains (value))
                                        throw new ArgumentException ("An item cannot be added more than once. To add an item again, you need to clone it.", "value");

                                value.Owner = owner;
                                list.Add (value);

                                owner.Sort (false);
                                OnChange ();
                                owner.Redraw (true);
                                return value;
                        }

                        public virtual ListViewItem Add (string text)
                        {
                                ListViewItem item = new ListViewItem (text);
                                return this.Add (item);
                        }

                        public virtual ListViewItem Add (string text, int imageIndex)
                        {
                                ListViewItem item = new ListViewItem (text, imageIndex);
                                return this.Add (item);
                        }

                        public void AddRange (ListViewItem [] values)
                        {
                                list.Clear ();

                                foreach (ListViewItem item in values) {
                                        item.Owner = owner;
                                        list.Add (item);
                                }

                                owner.Sort (false);
                                OnChange ();
                                owner.Redraw (true);
                        }

                        public virtual void Clear ()
                        {
                                owner.SetFocusedItem (null);
                                owner.h_scroll.Value = owner.v_scroll.Value = 0;
                                list.Clear ();
                                OnChange ();
                                owner.Redraw (true);
                        }

                        public bool Contains (ListViewItem item)
                        {
                                return list.Contains (item);
                        }

                        public void CopyTo (Array dest, int index)
                        {
                                list.CopyTo (dest, index);
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                return list.GetEnumerator ();
                        }

                        int IList.Add (object item)
                        {
                                int result;
                                ListViewItem li;

                                if (item is ListViewItem) {
                                        li = (ListViewItem) item;
                                        if (list.Contains (li))
                                                throw new ArgumentException ("An item cannot be added more than once. To add an item again, you need to clone it.", "item");
                                }
                                else
                                        li = new ListViewItem (item.ToString ());

                                li.Owner = owner;
                                result = list.Add (li);
                                OnChange ();
                                owner.Redraw (true);

                                return result;
                        }

                        bool IList.Contains (object item)
                        {
                                return list.Contains (item);
                        }

                        int IList.IndexOf (object item)
                        {
                                return list.IndexOf (item);
                        }

                        void IList.Insert (int index, object item)
                        {
                                if (item is ListViewItem)
                                        this.Insert (index, (ListViewItem) item);
                                else
                                        this.Insert (index, item.ToString ());
                        }

                        void IList.Remove (object item)
                        {
                                Remove ((ListViewItem) item);
                        }

                        public int IndexOf (ListViewItem item)
                        {
                                return list.IndexOf (item);
                        }

                        public ListViewItem Insert (int index, ListViewItem item)
                        {
                                if (index < 0 || index > list.Count)
                                        throw new ArgumentOutOfRangeException ("index");

                                if (list.Contains (item))
                                        throw new ArgumentException ("An item cannot be added more than once. To add an item again, you need to clone it.", "item");

                                item.Owner = owner;
                                list.Insert (index, item);
                                OnChange ();
                                owner.Redraw (true);
                                return item;
                        }

                        public ListViewItem Insert (int index, string text)
                        {
                                return this.Insert (index, new ListViewItem (text));
                        }

                        public ListViewItem Insert (int index, string text, int imageIndex)
                        {
                                return this.Insert (index, new ListViewItem (text, imageIndex));
                        }

                        public virtual void Remove (ListViewItem item)
                        {
                                if (!list.Contains (item))
                                        return;
                                        
                                list.Remove (item);
                                OnChange ();
                                owner.Redraw (true);                            
                        }

                        public virtual void RemoveAt (int index)
                        {
                                if (index < 0 || index >= Count)
                                        throw new ArgumentOutOfRangeException ("index");
                                list.RemoveAt (index);
                                OnChange ();
                                owner.Redraw (false);
                        }
                        #endregion      // Public Methods

                        internal event CollectionChangedHandler Changed;

                        internal void Sort (IComparer comparer)
                        {
                                list.Sort (comparer);
                                OnChange ();
                        }

                        internal void OnChange ()
                        {
                                if (Changed != null)
                                        Changed ();
                        }
                }       // ListViewItemCollection

                public class SelectedIndexCollection : IList, ICollection, IEnumerable
                {
                        private readonly ListView owner;

                        #region Public Constructor
                        public SelectedIndexCollection (ListView owner)
                        {
                                this.owner = owner;
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get {
                                        return owner.SelectedItems.Count;
                                }
                        }

                        public bool IsReadOnly {
                                get { return true; }
                        }

                        public int this [int index] {
                                get {
                                        int [] indices = GetIndices ();
                                        if (index < 0 || index >= indices.Length)
                                                throw new ArgumentOutOfRangeException ("index");
                                        return indices [index];
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return false; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return true; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set { throw new NotSupportedException ("SetItem operation is not supported."); }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public bool Contains (int selectedIndex)
                        {
                                int [] indices = GetIndices ();
                                for (int i = 0; i < indices.Length; i++) {
                                        if (indices [i] == selectedIndex)
                                                return true;
                                }
                                return false;
                        }

                        public void CopyTo (Array dest, int index)
                        {
                                int [] indices = GetIndices ();
                                Array.Copy (indices, 0, dest, index, indices.Length);
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                int [] indices = GetIndices ();
                                return indices.GetEnumerator ();
                        }

                        int IList.Add (object value)
                        {
                                throw new NotSupportedException ("Add operation is not supported.");
                        }

                        void IList.Clear ()
                        {
                                throw new NotSupportedException ("Clear operation is not supported.");
                        }

                        bool IList.Contains (object selectedIndex)
                        {
                                if (!(selectedIndex is int))
                                        return false;
                                return Contains ((int) selectedIndex);
                        }

                        int IList.IndexOf (object selectedIndex)
                        {
                                if (!(selectedIndex is int))
                                        return -1;
                                return IndexOf ((int) selectedIndex);
                        }

                        void IList.Insert (int index, object value)
                        {
                                throw new NotSupportedException ("Insert operation is not supported.");
                        }

                        void IList.Remove (object value)
                        {
                                throw new NotSupportedException ("Remove operation is not supported.");
                        }

                        void IList.RemoveAt (int index)
                        {
                                throw new NotSupportedException ("RemoveAt operation is not supported.");
                        }

                        public int IndexOf (int selectedIndex)
                        {
                                int [] indices = GetIndices ();
                                for (int i = 0; i < indices.Length; i++) {
                                        if (indices [i] == selectedIndex)
                                                return i;
                                }
                                return -1;
                        }
                        #endregion      // Public Methods

                        private int [] GetIndices ()
                        {
                                ArrayList selected_items = owner.SelectedItems.List;
                                int [] indices = new int [selected_items.Count];
                                for (int i = 0; i < selected_items.Count; i++) {
                                        ListViewItem item = (ListViewItem) selected_items [i];
                                        indices [i] = item.Index;
                                }
                                return indices;
                        }
                }       // SelectedIndexCollection

                public class SelectedListViewItemCollection : IList, ICollection, IEnumerable
                {
                        private readonly ListView owner;
                        private ArrayList list;

                        #region Public Constructor
                        public SelectedListViewItemCollection (ListView owner)
                        {
                                this.owner = owner;
                                this.owner.Items.Changed += new CollectionChangedHandler (
                                        ItemsCollection_Changed);
                        }
                        #endregion      // Public Constructor

                        #region Public Properties
                        [Browsable (false)]
                        public int Count {
                                get {
                                        if (!owner.IsHandleCreated)
                                                return 0;
                                        return List.Count;
                                }
                        }

                        public bool IsReadOnly {
                                get { return true; }
                        }

                        public ListViewItem this [int index] {
                                get {
                                        ArrayList selected_items = List;
                                        if (!owner.IsHandleCreated || index < 0 || index >= selected_items.Count)
                                                throw new ArgumentOutOfRangeException ("index");
                                        return (ListViewItem) selected_items [index];
                                }
                        }

                        bool ICollection.IsSynchronized {
                                get { return false; }
                        }

                        object ICollection.SyncRoot {
                                get { return this; }
                        }

                        bool IList.IsFixedSize {
                                get { return true; }
                        }

                        object IList.this [int index] {
                                get { return this [index]; }
                                set { throw new NotSupportedException ("SetItem operation is not supported."); }
                        }
                        #endregion      // Public Properties

                        #region Public Methods
                        public void Clear ()
                        {
                                if (!owner.IsHandleCreated)
                                        return;

                                foreach (ListViewItem item in List)
                                        item.Selected = false;
                        }

                        public bool Contains (ListViewItem item)
                        {
                                if (!owner.IsHandleCreated)
                                        return false;
                                return List.Contains (item);
                        }

                        public void CopyTo (Array dest, int index)
                        {
                                if (!owner.IsHandleCreated)
                                        return;
                                List.CopyTo (dest, index);
                        }

                        public IEnumerator GetEnumerator ()
                        {
                                if (!owner.IsHandleCreated)
                                        return (new ListViewItem [0]).GetEnumerator ();
                                return List.GetEnumerator ();
                        }

                        int IList.Add (object value)
                        {
                                throw new NotSupportedException ("Add operation is not supported.");
                        }

                        bool IList.Contains (object item)
                        {
                                if (!(item is ListViewItem))
                                        return false;
                                return Contains ((ListViewItem) item);
                        }

                        int IList.IndexOf (object item)
                        {
                                if (!(item is ListViewItem))
                                        return -1;
                                return IndexOf ((ListViewItem) item);
                        }

                        void IList.Insert (int index, object value)
                        {
                                throw new NotSupportedException ("Insert operation is not supported.");
                        }

                        void IList.Remove (object value)
                        {
                                throw new NotSupportedException ("Remove operation is not supported.");
                        }

                        void IList.RemoveAt (int index)
                        {
                                throw new NotSupportedException ("RemoveAt operation is not supported.");
                        }

                        public int IndexOf (ListViewItem item)
                        {
                                if (!owner.IsHandleCreated)
                                        return -1;
                                return List.IndexOf (item);
                        }
                        #endregion      // Public Methods

                        internal ArrayList List {
                                get {
                                        if (list == null) {
                                                list = new ArrayList ();
                                                foreach (ListViewItem item in owner.Items) {
                                                        if (item.Selected)
                                                                list.Add (item);
                                                }
                                        }
                                        return list;
                                }
                        }

                        internal void Reset ()
                        {
                                // force re-population of list
                                list = null;
                        }

                        private void ItemsCollection_Changed ()
                        {
                                Reset ();
                        }
                }       // SelectedListViewItemCollection

                internal delegate void CollectionChangedHandler ();

                #endregion // Subclasses
        }
}