使用DoubleAnimation实现动画：
// 使用DoubleAnimation进行自动旋转
DoubleAnimation ^anim = gcnew DoubleAnimation();
//anim->IsCumulative = true;
anim->From = 0;
anim->To = 360;
anim->Duration = Duration(TimeSpan(0, 0, 6));
anim->RepeatBehavior = RepeatBehavior::Forever;
rotation->BeginAnimation(rotation->AngleProperty, anim);