UndoRedoChanged Event

Occurs when the undo or redo buffer changes.

Syntax

C#
Visual Basic
Objective-C
Java
C++

public event EventHandler UndoRedoChanged

'Declaration
 
Public Event UndoRedoChanged As EventHandler

'Usage
 
Dim instance As AnnAutomation
Dim handler As EventHandler
 
AddHandler instance.UndoRedoChanged, handler

public:
event EventHandler^ UndoRedoChanged

This event will be fired when the undo/redo buffer changes. This gives the application a chance to update the user interface if needed.

The undo/redo buffer changes whenever an object inside the Container changes either by user interaction through the user interface or by code.

You can use the CanUndo and CanRedo property to determine whether this AnnAutomation can undo or redo an operation.

For more information, refer to Undoing Automation Operations.

This example updates an Undo and Redo menu handler's status.

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

Copy Code

Imports Leadtools
Imports Leadtools.Annotations
Imports Leadtools.WinForms
Imports Leadtools.Drawing

Public Sub AnnAutomation_UndoRedoChanged(ByVal manager As AnnAutomationManager)
   ' subscribe to the UndoRedoChanged event of all automations
   For Each automation As AnnAutomation In manager.Automations
      AddHandler automation.UndoRedoChanged, AddressOf automation_UndoRedoChanged
   Next automation
End Sub
Private Sub automation_UndoRedoChanged(ByVal sender As Object, ByVal e As EventArgs)
   Dim automation As AnnAutomation = CType(IIf(TypeOf sender Is AnnAutomation, sender, Nothing), AnnAutomation)

   ' assume _menuItemUndo is the Undo menu, and _menuItemRedo is the Redo menu
   _menuItemUndo.Enabled = automation.CanUndo
   _menuItemRedo.Enabled = automation.CanRedo
End Sub

using Leadtools;
using Leadtools.Annotations;
using Leadtools.WinForms;
using Leadtools.Drawing;

public void AnnAutomation_UndoRedoChanged(AnnAutomationManager manager)
{
   // subscribe to the UndoRedoChanged event of all automations
   foreach(AnnAutomation automation in manager.Automations)
      automation.UndoRedoChanged += new EventHandler(automation_UndoRedoChanged);
}
private void automation_UndoRedoChanged(object sender, EventArgs e)
{
   AnnAutomation automation = sender as AnnAutomation;

   // assume _menuItemUndo is the Undo menu, and _menuItemRedo is the Redo menu
   _menuItemUndo.Enabled = automation.CanUndo;
   _menuItemRedo.Enabled = automation.CanRedo;
}

UndoRedoChanged Event

Reference