mcs/class/System.Web/System.Web.UI.WebControls/ListBox.cs

   1 //
   2 // System.Web.UI.WebControls.ListBox.cs
   3 //
   4 // Authors:
   5 //   Gaurav Vaish (gvaish@iitk.ac.in)
   6 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   7 //
   8 // (C) Gaurav Vaish (2002)
   9 // (C) 2003 Andreas Nahr
  10 //\r
  11 \r
  12 using System;\r
  13 using System.Drawing;\r
  14 using System.Collections;\r
  15 using System.Collections.Specialized;\r
  16 using System.ComponentModel;\r
  17 using System.Globalization;\r
  18 using System.Web;\r
  19 using System.Web.UI;\r
  20 \r
  21 namespace System.Web.UI.WebControls\r
  22 {\r
  23         [ValidationProperty("SelectedItem")]\r
  24         public class ListBox : ListControl, IPostBackDataHandler\r
  25         {\r
  26                 public ListBox () : base ()\r
  27                 {\r
  28                 }\r
  29
  30                 [Browsable (false)]\r
  31                 public override Color BorderColor\r
  32                 {\r
  33                         get { return base.BorderColor; }\r
  34                         set { base.BorderColor = value; }\r
  35                 }\r
  36
  37                 [Browsable (false)]\r
  38                 public override BorderStyle BorderStyle\r
  39                 {\r
  40                         get { return base.BorderStyle; }\r
  41                         set { base.BorderStyle = value; }\r
  42                 }\r
  43
  44                 [Browsable (false)]\r
  45                 public override Unit BorderWidth\r
  46                 {\r
  47                         get { return base.BorderWidth; }\r
  48                         set { base.BorderWidth = value; }\r
  49                 }\r
  50
  51
  52                 [DefaultValue (4), Bindable (true), WebCategory ("Appearance")]
  53                 [WebSysDescription ("The number of rows displayed by the control.")]\r
  54                 public virtual int Rows\r
  55                 {\r
  56                         get {\r
  57                                 object o = ViewState ["Rows"];\r
  58                                 return (o == null) ? 4 : (int) o;\r
  59                         }\r
  60 \r
  61                         set {\r
  62                                 if (value < 1 || value > 2000)\r
  63                                         throw new ArgumentOutOfRangeException ("value", "Rows value has to be >= 0 and <= 2000.");\r
  64 \r
  65                                 ViewState ["Rows"] = value;\r
  66                         }\r
  67                 }\r
  68
  69                 [DefaultValue (typeof (ListSelectionMode), "Single"), WebCategory ("Behavior")]
  70                 [WebSysDescription ("The mode describing how the entries can be selected.")]\r
  71                 public virtual ListSelectionMode SelectionMode\r
  72                 {\r
  73                         get\r
  74                         {\r
  75                                 object o = ViewState ["SelectionMode"];\r
  76                                 return (o == null) ? ListSelectionMode.Single : (ListSelectionMode) o;\r
  77                         }\r
  78                         set\r
  79                         {\r
  80                                 if (!Enum.IsDefined (typeof (ListSelectionMode), value))\r
  81                                         throw new ArgumentOutOfRangeException ("value", "Only valid enumeration members are allowed");\r
  82                                 ViewState ["SelectionMode"] = value;\r
  83                         }\r
  84                 }\r
  85
  86                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  87                 [Bindable (false), EditorBrowsable (EditorBrowsableState.Never)]\r
  88                 public override string ToolTip\r
  89                 {\r
  90                         get { return String.Empty; }\r
  91                         set { /* Don't do anything. */ }\r
  92                 }\r
  93 \r
  94                 protected override void AddAttributesToRender (HtmlTextWriter writer)\r
  95                 {\r
  96                         if (Page != null)\r
  97                                 Page.VerifyRenderingInServerForm (this);\r
  98 \r
  99                         writer.AddAttribute (HtmlTextWriterAttribute.Name, UniqueID);\r
 100                         base.AddAttributesToRender (writer);\r
 101                         writer.AddAttribute (HtmlTextWriterAttribute.Size,\r
 102                                              Rows.ToString (NumberFormatInfo.InvariantInfo));\r
 103 \r
 104                         if (SelectionMode == ListSelectionMode.Multiple)\r
 105                                 writer.AddAttribute (HtmlTextWriterAttribute.Multiple, "multiple");\r
 106 \r
 107                         if (AutoPostBack && Page != null){\r
 108                                 writer.AddAttribute (HtmlTextWriterAttribute.Onchange,\r
 109                                                      Page.GetPostBackClientEvent (this, ""));\r
 110                                 writer.AddAttribute ("language", "javascript");\r
 111                         }\r
 112                 }\r
 113 \r
 114                 protected override void OnPreRender (EventArgs e)\r
 115                 {\r
 116                         base.OnPreRender (e);\r
 117                         if (Page != null && SelectionMode == ListSelectionMode.Multiple && Enabled)\r
 118                                 Page.RegisterRequiresPostBack(this);\r
 119                 }\r
 120 \r
 121                 protected override void RenderContents (HtmlTextWriter writer)\r
 122                 {\r
 123                         bool isMultAllowed = (SelectionMode == ListSelectionMode.Multiple);\r
 124                         bool selMade = false;\r
 125                         foreach (ListItem current in Items){\r
 126                                 writer.WriteBeginTag ("option");\r
 127                                 if (current.Selected){\r
 128                                         if (!isMultAllowed && selMade)\r
 129                                                 throw new HttpException ("Cannot_MultiSelect_In_Single_Mode");\r
 130                                         selMade = true;\r
 131                                         writer.WriteAttribute ("selected", "selected");\r
 132                                 }\r
 133                                 writer.WriteAttribute ("value", current.Value, true);\r
 134                                 writer.Write ('>');\r
 135                                 writer.Write (HttpUtility.HtmlEncode (current.Text));\r
 136                                 writer.WriteEndTag ("option");\r
 137                                 writer.WriteLine ();\r
 138                         }\r
 139                 }\r
 140 \r
 141                 bool IPostBackDataHandler.LoadPostData (string postDataKey,\r
 142                                                         NameValueCollection postCollection)\r
 143                 {\r
 144                         string[] vals = postCollection.GetValues (postDataKey);\r
 145                         bool updated = false;\r
 146                         if (vals != null){\r
 147                                 if (SelectionMode == ListSelectionMode.Single){\r
 148                                         int index = Items.FindByValueInternal (vals [0]);\r
 149                                         if (SelectedIndex != index){\r
 150                                                 SelectedIndex = index;\r
 151                                                 updated       = true;\r
 152                                         }\r
 153                                 } else {\r
 154                                         ArrayList indices = SelectedIndices;
 155                                         int length = vals.Length;
 156                                         ArrayList final = new ArrayList (length);
 157                                         foreach (string current in vals)\r
 158                                                 final.Add (Items.FindByValueInternal (current));\r
 159
 160                                         if (indices.Count == length) {
 161                                                 for (int ctr = 0; ctr < length; ctr++){
 162                                                         if (((int) final [ctr]) != ((int) indices [ctr])){
 163                                                                 updated = true;\r
 164                                                                 break;\r
 165                                                         }\r
 166                                                 }\r
 167                                         } else {\r
 168                                                 updated = true;\r
 169                                         }\r
 170                                         if (updated)
 171                                                 Select (final);
 172                                 }
 173                         } else {\r
 174                                 if (SelectedIndex != -1)\r
 175                                         SelectedIndex = -1;\r
 176                                 updated = true;\r
 177                         }\r
 178                         return updated;\r
 179                 }\r
 180 \r
 181                 void IPostBackDataHandler.RaisePostDataChangedEvent ()\r
 182                 {\r
 183                         OnSelectedIndexChanged (EventArgs.Empty);\r
 184                 }\r
 185         }\r
 186 }\r