mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/View/RubberBandSelector.cs

   1 //----------------------------------------------------------------
   2 // <copyright company="Microsoft Corporation">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //----------------------------------------------------------------
   6
   7 namespace System.Activities.Presentation.View
   8 {
   9     using System;
  10     using System.Activities.Presentation.Internal.PropertyEditing;
  11     using System.Activities.Presentation.Model;
  12     using System.Collections.Generic;
  13     using System.Runtime;
  14     using System.Windows;
  15     using System.Windows.Documents;
  16     using System.Windows.Input;
  17     using System.Windows.Media;
  18     using System.Windows.Shapes;
  19
  20     internal sealed class RubberBandSelector
  21     {
  22         private const double RubberBandThickness = 2;
  23         private EditingContext context;
  24         private Rectangle rubberBand;
  25         private List<WorkflowViewElement> views = new List<WorkflowViewElement>();
  26
  27         public RubberBandSelector(EditingContext context)
  28         {
  29             this.context = context;
  30             this.InitializeRubberBand();
  31         }
  32
  33         public bool IsSelected
  34         {
  35             get;
  36             set;
  37         }
  38
  39         // Relative to the scrollable content
  40         private Point StartPoint
  41         {
  42             get;
  43             set;
  44         }
  45
  46         // Relative to the scrollable content
  47         private Point EndPoint
  48         {
  49             get;
  50             set;
  51         }
  52
  53         // Relative to the scrollable content
  54         private Point MouseDownPointToScreen { get; set; }
  55
  56         private bool IsSelecting
  57         {
  58             get
  59             {
  60                 return this.ExtenstionSurface.Children.Contains(this.rubberBand);
  61             }
  62         }
  63
  64         private bool IsReadyForSelecting
  65         {
  66             get;
  67             set;
  68         }
  69
  70         private ExtensionSurface ExtenstionSurface
  71         {
  72             get
  73             {
  74                 return this.Designer.wfViewExtensionSurface;
  75             }
  76         }
  77
  78         private DesignerView Designer
  79         {
  80             get
  81             {
  82                 return this.context.Services.GetService<DesignerView>();
  83             }
  84         }
  85
  86         public void RegisterViewElement(WorkflowViewElement view)
  87         {
  88             if (!this.views.Contains(view))
  89             {
  90                 this.views.Add(view);
  91             }
  92         }
  93
  94         public void UnregisterViewElement(WorkflowViewElement view)
  95         {
  96             if (this.views.Contains(view))
  97             {
  98                 this.views.Remove(view);
  99             }
 100         }
 101
 102         public void OnScrollViewerMouseLeftButtonDown(MouseButtonEventArgs e)
 103         {
 104             this.IsSelected = false;
 105
 106             // Start rubber band selection if left button down is not handled by UI elements other than WorkflowViewElement.
 107             if (!e.Handled || this.Designer.ShouldStillAllowRubberBandEvenIfMouseLeftButtonDownIsHandled)
 108             {
 109                 if (DesignerView.IsMouseInViewport(e, this.Designer.scrollViewer) && !this.IsMouseOnDragHandle(e) && !this.IsMouseOverAdorner(e))
 110                 {
 111                     this.IsReadyForSelecting = true;
 112                     this.StartPoint = e.GetPosition(this.Designer.scrollableContent);
 113
 114                     this.MouseDownPointToScreen = this.Designer.scrollableContent.PointToScreen(this.StartPoint);
 115                     this.EndPoint = this.StartPoint;
 116                 }
 117             }
 118         }
 119
 120         public void OnScrollViewerMouseMove(MouseEventArgs e)
 121         {
 122             if (e.LeftButton == MouseButtonState.Pressed && this.IsReadyForSelecting)
 123             {
 124                 Point position = e.GetPosition(this.Designer.scrollableContent);
 125                 Point positionToScreen = this.Designer.scrollableContent.PointToScreen(position);
 126                 if (!this.IsSelecting && (Math.Abs(positionToScreen.X - this.MouseDownPointToScreen.X) > SystemParameters.MinimumHorizontalDragDistance ||
 127                     Math.Abs(positionToScreen.Y - this.MouseDownPointToScreen.Y) > SystemParameters.MinimumVerticalDragDistance))
 128                 {
 129                     this.AddRubberBand();
 130                     if (!this.Designer.scrollableContent.IsMouseCaptured)
 131                     {
 132                         this.Designer.scrollableContent.CaptureMouse();
 133                     }
 134
 135                     e.Handled = true;
 136                 }
 137
 138                 if (this.IsSelecting)
 139                 {
 140                     this.EndPoint = position;
 141                     this.UpdateRubberBand();
 142                     AutoScrollHelper.AutoScroll(e.GetPosition(this.Designer.scrollViewer), this.Designer.scrollViewer, 0.2);
 143                     e.Handled = true;
 144                 }
 145             }
 146         }
 147
 148         public void OnScrollViewerPreviewMouseLeftButtonUp(MouseEventArgs e)
 149         {
 150             if (this.IsSelecting)
 151             {
 152                 this.EndPoint = e.GetPosition(this.Designer.scrollableContent);
 153                 this.Select(Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl));
 154                 this.IsSelected = true;
 155             }
 156
 157             this.StopSelecting();
 158         }
 159
 160         public void OnScrollViewerMouseLeave()
 161         {
 162             this.StopSelecting();
 163         }
 164
 165         public void OnScrollViewerEscapeKeyDown()
 166         {
 167             this.StopSelecting();
 168         }
 169
 170         private static Point ClipPoint(Point point)
 171         {
 172             // Negative vaule means the top left corner of the rubber band is outside of the viewport.
 173             // We need to clip the rubber band since a very negative value will cause some WPF display issues.
 174             // But we use -RubberBandThickness instead of 0 to clip so that the border of the rubber band that should be outside of the viewport is still outside.
 175             return new Point(point.X < -RubberBandThickness ? -RubberBandThickness : point.X, point.Y < -RubberBandThickness ? -RubberBandThickness : point.Y);
 176         }
 177
 178         private void StopSelecting()
 179         {
 180             this.IsReadyForSelecting = false;
 181             if (this.IsSelecting)
 182             {
 183                 this.RemoveRubberBand();
 184                 if (this.Designer.scrollableContent.IsMouseCaptured)
 185                 {
 186                     this.Designer.scrollableContent.ReleaseMouseCapture();
 187                 }
 188             }
 189         }
 190
 191         private bool IsMouseOnDragHandle(MouseButtonEventArgs e)
 192         {
 193             HitTestResult result = VisualTreeHelper.HitTest(this.Designer.scrollableContent, e.GetPosition(this.Designer.scrollableContent));
 194             if (result != null)
 195             {
 196                 WorkflowViewElement view = VisualTreeUtils.FindVisualAncestor<WorkflowViewElement>(result.VisualHit);
 197                 if (view != null && view.DragHandle != null)
 198                 {
 199                     GeneralTransform transform = view.DragHandle.TransformToAncestor(this.Designer);
 200                     Fx.Assert(transform != null, "transform should not be null");
 201                     Point topLeft = transform.Transform(new Point(0, 0));
 202                     Point bottomRight = transform.Transform(new Point(view.DragHandle.ActualWidth, view.DragHandle.ActualHeight));
 203                     Rect dragHandleRect = new Rect(topLeft, bottomRight);
 204                     if (dragHandleRect.Contains(e.GetPosition(this.Designer)))
 205                     {
 206                         return true;
 207                     }
 208                 }
 209             }
 210
 211             return false;
 212         }
 213
 214         private bool IsMouseOverAdorner(MouseButtonEventArgs e)
 215         {
 216             HitTestResult result = VisualTreeHelper.HitTest(this.Designer.scrollViewer, e.GetPosition(this.Designer.scrollViewer));
 217             return result != null && VisualTreeUtils.FindVisualAncestor<Adorner>(result.VisualHit) != null;
 218         }
 219
 220         private void AddRubberBand()
 221         {
 222             if (!this.ExtenstionSurface.Children.Contains(this.rubberBand))
 223             {
 224                 this.ExtenstionSurface.Children.Add(this.rubberBand);
 225             }
 226             else
 227             {
 228                 Fx.Assert(false, "Old rubber band was not correctly removed.");
 229             }
 230         }
 231
 232         private void RemoveRubberBand()
 233         {
 234             if (this.ExtenstionSurface.Children.Contains(this.rubberBand))
 235             {
 236                 this.ExtenstionSurface.Children.Remove(this.rubberBand);
 237             }
 238             else
 239             {
 240                 Fx.Assert(false, "Rubber band was not correctly added.");
 241             }
 242         }
 243
 244         private void UpdateRubberBand()
 245         {
 246             if (this.ExtenstionSurface.Children.Contains(this.rubberBand))
 247             {
 248                 // Transform the start and end points to be relative to the extension surface by transforming to the common ancestor (DesignerView) first
 249                 GeneralTransform transform1 = this.Designer.scrollableContent.TransformToAncestor(this.Designer);
 250                 GeneralTransform transform2 = this.Designer.TransformToDescendant(this.ExtenstionSurface);
 251                 Point start = ClipPoint(transform2.Transform(transform1.Transform(this.StartPoint)));
 252                 Point end = ClipPoint(transform2.Transform(transform1.Transform(this.EndPoint)));
 253                 Rect rect = new Rect(start, end);
 254                 this.rubberBand.Width = rect.Width;
 255                 this.rubberBand.Height = rect.Height;
 256                 this.rubberBand.InvalidateVisual();
 257                 ExtensionSurface.SetPosition(this.rubberBand, rect.TopLeft);
 258             }
 259             else
 260             {
 261                 Fx.Assert(false, "Rubber band was not correctly added.");
 262             }
 263         }
 264
 265         private void Select(bool isCtrlKeyDown)
 266         {
 267             bool isRubberBandEmpty = true;
 268             Rect rubberBandRect = new Rect(this.StartPoint, this.EndPoint);
 269             List<ModelItem> selectedModelItems = new List<ModelItem>();
 270             foreach (WorkflowViewElement view in this.views)
 271             {
 272                 GeneralTransform transform = view.TransformToAncestor(this.Designer.scrollableContent);
 273                 Point location = transform.Transform(new Point(0, 0));
 274                 Rect rect = new Rect(location.X, location.Y, view.ActualWidth, view.ActualHeight);
 275                 if (rubberBandRect.Contains(rect))
 276                 {
 277                     isRubberBandEmpty = false;
 278                     if (isCtrlKeyDown)
 279                     {
 280                         Selection.Toggle(this.context, view.ModelItem);
 281                     }
 282                     else
 283                     {
 284                         // Make sure the rubber-band selection has the same order
 285                         // and keyboard focus as ctrl+click one by one, which
 286                         // 1) model item is added in reverse order
 287                         // 2) last model item, which is the first in selection array,
 288                         //    gets focus
 289                         selectedModelItems.Insert(0, view.ModelItem);
 290                     }
 291                 }
 292             }
 293
 294             if (selectedModelItems.Count > 0)
 295             {
 296                 Keyboard.Focus(selectedModelItems[0].View as IInputElement);
 297                 this.context.Items.SetValue(new Selection(selectedModelItems));
 298             }
 299
 300             if (isRubberBandEmpty && !isCtrlKeyDown
 301                 && this.ShouldClearSelectioinIfNothingSelected())
 302             {
 303                 this.context.Items.SetValue(new Selection());
 304             }
 305         }
 306
 307         private bool ShouldClearSelectioinIfNothingSelected()
 308         {
 309             Selection curSelection = this.context.Items.GetValue<Selection>();
 310             if (curSelection == null || curSelection.SelectionCount == 0)
 311             {
 312                 return false;
 313             }
 314
 315             // only one ModelItem is selected and the ModelItem is root designer.
 316             // do not clear selection
 317             if (curSelection.SelectionCount == 1)
 318             {
 319                 ModelItem item = curSelection.PrimarySelection;
 320                 WorkflowViewElement view = item == null ? null : (item.View as WorkflowViewElement);
 321                 if (view != null && view.IsRootDesigner)
 322                 {
 323                     return false;
 324                 }
 325             }
 326
 327             return true;
 328         }
 329
 330         private void InitializeRubberBand()
 331         {
 332             this.rubberBand = new Rectangle();
 333             this.rubberBand.StrokeThickness = RubberBandThickness;
 334             this.rubberBand.Stroke = WorkflowDesignerColors.RubberBandRectangleBrush;
 335             this.rubberBand.Fill = WorkflowDesignerColors.RubberBandRectangleBrush.Clone();
 336             this.rubberBand.Fill.Opacity = 0.2;
 337         }
 338     }
 339 }