/// <summary> 当页面被卸载时执行 </summary>
private void Page_Unloaded(object sender, RoutedEventArgs e)
{
TilesView.RemoveHandler(UIElement.KeyDownEvent, keyDownHandler);
keyDownHandler = null;
}
/// <summary> 当页面加载完毕时执行 </summary>
private void Page_Loaded(object sender, RoutedEventArgs e)
{
this.keyDownHandler = new KeyEventHandler(TilesView_KeyDown);
TilesView.AddHandler(UIElement.KeyDownEvent, keyDownHandler, true);
}