Blend生成的TransformGroup如何引用?

很多时候，blend在制作动画时，会自动为对象生成如下代码:

 

< Rectangle  Fill ="White"  Stroke ="Black"  HorizontalAlignment ="Center"  VerticalAlignment ="Center"  Width ="300"  Height ="30"  RenderTransformOrigin ="0.5,0.5"  x:Name ="rect" >
     < Rectangle.RenderTransform >
      < TransformGroup >
       < ScaleTransform />
       < SkewTransform />
       < RotateTransform />
       < TranslateTransform />
      </ TransformGroup >
     </ Rectangle.RenderTransform >
    </ Rectangle >

 

如果想在cs代码中动态控制，就得先知道如何引用它们，在不借助x:Name的情况下，可以这么做: 

 

private   void  Button_Click( object  sender, RoutedEventArgs e)
        {            

             RotateTransform r  =  (rect.RenderTransform  as  TransformGroup).Children[ 2 ]  as  RotateTransform;

            DoubleAnimation dblAnim  =   new  DoubleAnimation() { Duration  =  TimeSpan.FromSeconds( 1 ), To  =   135.0 , EasingFunction  =   new  BackEase() { EasingMode  =  EasingMode.EaseInOut } };         

            Storyboard.SetTarget(dblAnim, r);
            Storyboard.SetTargetProperty(dblAnim,  new  PropertyPath(RotateTransform.AngleProperty));

            Storyboard sb  =   new  Storyboard();
            sb.Children.Add(dblAnim);           
            sb.AutoReverse  =   true ;
            sb.Begin();           

        }
    }

 

 

上面的代码，将生成一段动画：1秒钟内将矩形旋转135度