public static void AddPreviewDragMoveHandler(FrameworkElement frameworkElement, DragMoveRoutedEventHandler handler)
 {
     frameworkElement.AddRoutedHandler(PreviewDragMoveEvent, handler);
 }
        public static void AddDragLeaveHandler(FrameworkElement frameworkElement, RoutedEventHandler handler)
        {
            AddDragEnterOverLeaveHandler(frameworkElement, handler);

            frameworkElement.AddRoutedHandler(DragLeaveEvent, handler);
        }
 public static void AddDragStartedHandler(FrameworkElement frameworkElement, DragStartedRoutedEventHandler handler)
 {
     frameworkElement.AddRoutedHandler(DragStartedEvent, handler);
 }
 public static void AddPreviewDragOverHandler(FrameworkElement frameworkElement, RoutedEventHandler handler)
 {
     frameworkElement.AddRoutedHandler(PreviewDragOverEvent, handler);
 }