private static void RemoveEventHandlers(TextBoxBase textBox, UndoManager manager)
{
if (textBox != null && manager != null)
{
textBox.RemoveHandler(CommandManager.PreviewExecutedEvent, new ExecutedRoutedEventHandler(manager.ExecutedHandler));
textBox.TextChanged -= new TextChangedEventHandler(manager.TextChangedHandler);
}
}
/// <summary>
/// Removes this object from the chain of events that notify listeners of changes to the content.
/// </summary>
/// <param name="dependencyObject">The target element that will no longer be registered for state change events.</param>
public override void Unregister(DependencyObject dependencyObject)
{
// This will remove this object from the chain of events that keep the control integrated with the Undo/Redo operations
// in a scope.
TextBoxBase textBox = dependencyObject as TextBoxBase;
textBox.RemoveHandler(TextBoxBase.TextChangedEvent, new TextChangedEventHandler(TextChangedHandler));
}