Question

我创建了一个简单的StackPanel子类，我可以使用动画TranslateTransform在屏幕上移动。它看起来像这样：

public class MovingStackPanel : StackPanel
{
    public void BeginMove(Point translatePosition)
    {
        RenderTransform = new TranslateTransform();
        Duration d = new Duration(new TimeSpan(0, 0, 0, 0, 400));
        DoubleAnimation x = new DoubleAnimation(translatePosition.X, d);
        DoubleAnimation y = new DoubleAnimation(translatePosition.Y, d);
        /*
        Storyboard.SetTarget(x, RenderTransform);
        Storyboard.SetTargetProperty(x, new PropertyPath("X"));

        Storyboard.SetTarget(y, RenderTransform);
        Storyboard.SetTargetProperty(y, new PropertyPath("Y"));

        Storyboard sb = new Storyboard();
        sb.Children.Add(x);
        sb.Children.Add(y);
        sb.Completed += sb_Completed;
        sb.Begin();
        */
        RenderTransform.BeginAnimation(TranslateTransform.XProperty, x);
        RenderTransform.BeginAnimation(TranslateTransform.YProperty, y);
    }

    void sb_Completed(object sender, EventArgs e)
    {
        Console.WriteLine("Completed.");
    }
}

这是我的问题：如果我直接为X和Y属性设置动画，就像上面的代码一样，它可以工作。但是，如果我使用它上面的注释掉的代码，这实际上是可以想象的代码中Storyboard的最简单的创建，没有任何反应。动画运行 - 至少，已完成事件被提升 - 但屏幕上没有任何变化。

显然我做错了什么，但我看不出它是什么。在我看过的代码中创建故事板的每个例子看起来都是这样的。很明显我还不知道动画和故事板的内容：它是什么？

Answer 1

事实证明，在这种情况下你不能使用属性路径语法，因为被动画化的属性不是FrameworkElement的属性。至少，这就是我如何解释当我做出Anvaka建议的变化时我得到的非常令人困惑的异常：

Cannot automatically create animation clone for frozen property values on     
'System.Windows.Media.TranslateTransform' objects. Only FrameworkElement and 
FrameworkContentElement (or derived) types are supported.

要设置动画，似乎我必须使用NameScope并使用SetTargetName来命名TransformElement。然后，只要我将名称范围的FrameworkElement传递给Begin方法，故事板就可以找到对象和属性并为它们设置动画，这一切都有效。最终结果如下：

public void BeginMove(Point translatePosition)
{
    NameScope.SetNameScope(this, new NameScope());

    RenderTransform = new TranslateTransform();
    RegisterName("TranslateTransform", RenderTransform);

    Duration d = new Duration(new TimeSpan(0, 0, 0, 0, 400));
    DoubleAnimation x = new DoubleAnimation(translatePosition.X, d);
    DoubleAnimation y = new DoubleAnimation(translatePosition.Y, d);

    Storyboard.SetTargetName(x, "TranslateTransform");
    Storyboard.SetTargetProperty(x, new PropertyPath(TranslateTransform.XProperty));

    Storyboard.SetTargetName(y, "TranslateTransform");
    Storyboard.SetTargetProperty(y, new PropertyPath(TranslateTransform.YProperty));

    Storyboard sb = new Storyboard();
    sb.Children.Add(x);
    sb.Children.Add(y);
    sb.Completed += sb_Completed;

    // you must pass this to the Begin method, otherwise the timeline won't be
    // able to find the named objects it's animating because it doesn't know
    // what name scope to look in

    sb.Begin(this);

}

Answer 2

这是property path语法。以下方法有效：

public void BeginMove(Point translatePosition)
{
  RenderTransform = new TranslateTransform();
  Duration d = new Duration(new TimeSpan(0, 0, 0, 0, 400));
  DoubleAnimation x = new DoubleAnimation(translatePosition.X, d);
  DoubleAnimation y = new DoubleAnimation(translatePosition.Y, d);

  Storyboard.SetTarget(x, this);
  Storyboard.SetTargetProperty(x, 
              new PropertyPath("(UIElement.RenderTransform).(TranslateTransform.X)"));

  Storyboard.SetTarget(y, this);
  Storyboard.SetTargetProperty(y, 
              new PropertyPath("(UIElement.RenderTransform).(TranslateTransform.Y)"));

  Storyboard sb = new Storyboard();
  sb.Children.Add(x);
  sb.Children.Add(y);
  sb.Completed += sb_Completed;
  sb.Begin();

  //RenderTransform.BeginAnimation(TranslateTransform.XProperty, x);
  //RenderTransform.BeginAnimation(TranslateTransform.YProperty, y);
}

当我使用故事板时，为什么这些动画不起作用？

2 个答案: