mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/EditingScopeUndoUnit.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation
   6 {
   7     using System.Activities.Presentation.Model;
   8     using System.Runtime;
   9
  10     internal class EditingScopeUndoUnit : UndoUnit
  11     {
  12         private ModelTreeManager modelTreeManager;
  13         private EditingScope editingScope;
  14         private EditingContext context;
  15
  16         public EditingScopeUndoUnit(EditingContext context, ModelTreeManager modelTreeManager, EditingScope editingScope)
  17             : base(context)
  18         {
  19             Fx.Assert(context != null, "context cannot be null");
  20             Fx.Assert(modelTreeManager != null, "modelTreeManager cannot be null");
  21             Fx.Assert(editingScope != null, "editingScope cannot be null");
  22
  23             this.context = context;
  24             this.modelTreeManager = modelTreeManager;
  25             this.editingScope = editingScope;
  26             this.Description = this.editingScope.Description;
  27
  28             SaveGlobalState();
  29         }
  30
  31         public override void Redo()
  32         {
  33             this.modelTreeManager.StopTracking();
  34             try
  35             {
  36                 EditingScope redoEditingScope = this.modelTreeManager.CreateEditingScope(this.editingScope.Description);
  37                 redoEditingScope.Changes.AddRange(editingScope.Changes);
  38                 redoEditingScope.Complete();
  39             }
  40             finally
  41             {
  42                 this.modelTreeManager.StartTracking();
  43             }
  44             ApplyGlobalState();
  45         }
  46
  47         public override void Undo()
  48         {
  49             this.modelTreeManager.StopTracking();
  50             try
  51             {
  52                 EditingScope undoEditingScope = this.modelTreeManager.CreateEditingScope(this.editingScope.Description);
  53                 foreach (Change change in editingScope.Changes)
  54                 {
  55                     Change inverseChange = change.GetInverse();
  56                     if (inverseChange != null)
  57                     {
  58                         undoEditingScope.Changes.Add(inverseChange);
  59                     }
  60                 }
  61                 undoEditingScope.Changes.Reverse();
  62                 undoEditingScope.Complete();
  63             }
  64             finally
  65             {
  66                 this.modelTreeManager.StartTracking();
  67             }
  68             ApplyGlobalState();
  69         }
  70     }
  71 }