Begins a change block.
Assembly: PresentationFramework (in PresentationFramework.dll)
Note: When you call , you must also call EndChange to complete the change block otherwise an exception will be thrown.
A change block logically groups multiple changes into a single undo unit and prevents text content or selection change events from being raised until after the change block. This way you can make multiple edits to the text element without the danger of the text element being changed at the same time by another listener. A change block is created by calling the DeclareChangeBlock method. Calling the method causes all subsequent changes to be included in the specified change block until a corresponding call to the EndChange method is made.
The following example shows how to use the and EndChange methods to create a change block.
Dim myTextBox As New TextBox() ' Begin the change block. Once BeginChange() is called ' no text content or selection change events will be raised ' until EndChange is called. Also, all edits made within ' a BeginChange/EndChange block are wraped in a single undo block. myTextBox.BeginChange() ' Put some initial text in the TextBox. myTextBox.Text = "Initial text in TextBox" ' Make other changes if desired... ' Whenever BeginChange() is called EndChange() must also be ' called to end the change block. myTextBox.EndChange()
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