Uwp 如果端点为0，则CompositeTransform.TranslateY不起作用

我在转换UIElement时没有问题，如果端点被赋予除0以外的值。如果终点为0，起点为非零值，则不会设置动画。但是，它在xaml中使用相同的值，没有任何问题。我哪里做错了

        // Not works
        var startPoint = -200;
        var endPoint = 0;

        // works
        //var startPoint = 0;
        //var endPoint = 200;

        // Create the transform
        var moveTransform = new CompositeTransform();
        uIElement.RenderTransformOrigin = new Point(0.5, 0.5);
        uIElement.RenderTransform = moveTransform;
        var storyboard = new Storyboard();

        DoubleAnimationUsingKeyFrames animationKeyFrames2 = new DoubleAnimationUsingKeyFrames();

        var keyFrameStart2 = new EasingDoubleKeyFrame();
        keyFrameStart2.KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(0));
        keyFrameStart2.Value = startPoint;

        var keyFrameEnd2 = new EasingDoubleKeyFrame();
        keyFrameEnd2.KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(1000));
        keyFrameEnd2.Value = endPoint;

        animationKeyFrames2.KeyFrames.Add(keyFrameEnd2);

        Storyboard.SetTargetProperty(animationKeyFrames2,
            "(UIElement.RenderTransform).(CompositeTransform.TranslateY)");

        Storyboard.SetTarget(animationKeyFrames2, uIElement);
        storyboard.Children.Add(animationKeyFrames2);

        storyboard.Begin();

---

您需要在code

keyFrameStart2.Value=startPoint下添加以下代码

将

关键帧开始2

添加到

动画关键帧2。关键帧

设置起点：

animationKeyFrames2.KeyFrames.Add(keyFrameStart2);