//click undo
 public void HandleUndoButtonClick(object sender, System.EventArgs e)
 {
     _model.ClickUndo();
     _buttonUndo.Enabled = _model.GetUndoEnable();
     _buttonRedo.Enabled = _model.GetRedoEnable();
 }
 //click undo
 private void HandleUndoButtonClick(object sender, RoutedEventArgs e)
 {
     _model.ClickUndo();
     _undo.IsEnabled = _model.GetUndoEnable();
     _redo.IsEnabled = _model.GetRedoEnable();
 }