wp7 -动画

<Rectangle Width="100" Height="100" HorizontalAlignment="Left" VerticalAlignment="Top" Fill="Red" Name="darkMoon"/>           

　   DoubleAnimationUsingKeyFrames doublea = new DoubleAnimationUsingKeyFrames()
            {
                BeginTime = new TimeSpan(0, 0, 0, 2),
                SpeedRatio=1,
                Duration = new Duration(TimeSpan.FromSeconds(1)),
                AutoReverse = false,
                RepeatBehavior = new RepeatBehavior(20),
                FillBehavior = FillBehavior.HoldEnd
            };
            EasingDoubleKeyFrame key1 = new EasingDoubleKeyFrame()
            {
                KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(0)),
                Value = 0
            };
            EasingDoubleKeyFrame key2 = new EasingDoubleKeyFrame()
            {
                KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1)),
                Value = 100
            };
            EasingDoubleKeyFrame key3 = new EasingDoubleKeyFrame()
            {
                KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2)),
                Value = 200
            };
            EasingDoubleKeyFrame key4 = new EasingDoubleKeyFrame()
            {
                KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3)),
                Value = 300
            };
            doublea.KeyFrames.Add(key1);
            doublea.KeyFrames.Add(key2);
            doublea.KeyFrames.Add(key3);
            doublea.KeyFrames.Add(key4);

            Storyboard storyboard2 = new Storyboard();
            Storyboard.SetTarget(doublea, darkMoon);
            Storyboard.SetTargetProperty(doublea, new PropertyPath(WidthProperty));
            storyboard2.Children.Add(doublea);
            storyboard2.Begin();

////////////////////////////////////////////////////////////////////////////////////////////////////////

            DoubleAnimation doublea = new DoubleAnimation()
            {
                BeginTime = new TimeSpan(0, 0, 0, 2),
                From = 200,
                To = 300,
                Duration = new Duration(TimeSpan.FromSeconds(1)),
                AutoReverse = false,
                RepeatBehavior = new RepeatBehavior(20),
                FillBehavior = FillBehavior.HoldEnd
            };
            Storyboard storyboard2 = new Storyboard();
            Storyboard.SetTarget(doublea, darkMoon);
            Storyboard.SetTargetProperty(doublea, new PropertyPath(WidthProperty));
            storyboard2.Children.Add(doublea);
            storyboard2.Begin();