① 利用UIElement.OpacityMask屬性，用于改變對象區(qū)域的不透明度的畫筆?？梢允乖氐奶囟▍^(qū)域透明或部分透明，從而實現比較新穎的效果。
private void btnCancel_Click(object sender, RoutedEventArgs e)
{
this.IsEnabled = false;
LoginGrid.OpacityMask = this.Resources["ClosedBrush"] as LinearGradientBrush;
Storyboard std = this.Resources["ClosedStoryboard"] as Storyboard;
std.Completed += delegate { this.Close(); };
std.Begin();
}
