BeginUndo Method

WinRT C#
WinRT JavaScript

public virtual void BeginUndo()

 function Leadtools.Annotations.Automation.AnnAutomation.BeginUndo()

Use BeginUndo, EndUndo and CancelUndo to programmatically add a node to the undo stack maintained by this AnnAutomation. Typically, you add an undo node as follows:

Call the BeginUndo method before you make any changes to create a new node.
Perform any changes to the AnnAutomation object.
Call the EndUndo method to commit this undo node into the undo stack of the AnnAutomation object.
In case of errors (typically in a catch statement), call the CancelUndo method to remove the node and cancel the operation.

You do not need to manually call BeginUndo, EndUndo or CancelUndo when calling methods from this AnnAutomation object. The AnnAutomation object will internally do this for you. For example, when you call the DeleteSelectedObjects method to delete the object(s) currently being edited, the AnnAutomation object will perform the above sequence internally to add the undo node.

Use the UndoCapacity property to get or set the number of user actions that can be reversed using the Undo method, or re-applied using the Redo method. The default for the UndoCapacity property is 10 actions.

For information on undoing or redoing automation operations, refer to Undoing Annotation Automation Operations.

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

[TestMethod]
public void AnnAutomation_BeginUndo()
{
   // first create a new undo node
   _automation.BeginUndo();
   try
   {
      // add a new rectangle object
      AnnRectangleObject rectObj = new AnnRectangleObject();
      rectObj.Rect = LeadRectDHelper.Create(100, 100, 800, 800);
      rectObj.Stroke = AnnStroke.Create(AnnSolidColorBrush.Create("Blue"), LeadLengthDHelper.Create(1));
      rectObj.Fill = AnnSolidColorBrush.Create("Yellow");
      _automation.Container.Children.Add(rectObj);

      // Invalidate it
      _automation.Invalidate(LeadRectDHelper.Empty);

      // Select this object
      _automation.SelectObject(rectObj);

      // commit the undo node
      _automation.EndUndo();
   }
   catch (Exception ex)
   {
      // in case of errors, cancel the undo node
      _automation.CancelUndo();
      Debug.WriteLine(ex.Message);
      return;
   }

   Debug.WriteLine("Object has been added as is now selected. Next will call //Undo// to undo the operation");
   _automation.Undo();
   Debug.WriteLine("Operation has been undone. Next will call //Redo// to redo the operation");
   _automation.Redo();
   Debug.WriteLine("Object should be back and selected");
}

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

AnnAutomation Class
AnnAutomation Members