Protected Overridable Sub OnUndoRedoChanged( _
   ByVal e As EventArgs _
) 

Visual Basic (Usage)	Copy Code
Dim instance As AnnAutomation Dim e As EventArgs   instance.OnUndoRedoChanged(e)

protected virtual void OnUndoRedoChanged( 
   EventArgs e
)

protected:
virtual void OnUndoRedoChanged( 
   EventArgs^ e
) 

Parameters

e

An EventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. The OnUndoRedoChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class. Notes to Inheritors: When overriding OnUndoRedoChanged in a derived class, be sure to call the base class's OnUndoRedoChanged method so that registered delegates receive the event.

The UndoRedoChanged 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 property and the CanRedo property to determine whether this AnnAutomation can undo or redo an operation.

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

Reference