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当我使用故事板时,为什么这些动画不起作用?

storyboard animation wpf

Robert Rossney · 技术社区 · 15 年前

我已经创建了 StackPanel 我可以在屏幕上使用动画 TranslateTransform . 看起来是这样的:

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.");
    }
}

这里是我的问题:如果我像上面的代码那样直接设置x和y属性的动画,它就会工作。但如果我使用上面的注释掉的代码,这实际上是 Storyboard 在可以想象的代码中,什么都没有发生。动画运行-至少,完成的事件会被引发-但屏幕上没有任何变化。

显然我做错了什么,但我看不出是什么。我所看到的用代码创建故事板的每个例子都是这样的。很明显,关于动画和故事板的一些东西我还不知道:是什么?

2 回复 | 直到 13 年前

Robert Rossney 15 年前

事实证明,在这种情况下,不能使用属性路径语法,因为要设置动画的属性不是 FrameworkElement . 至少,当我做出安瓦卡建议的改变时,我是这样理解这个令人困惑的例外的:

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

要使它们成为动画,我必须使用 NameScope 和使用 SetTargetName 命名 TransformElement . 那么,只要我通过 框架元素 我将名称范围设置为 Begin 方法,故事板可以找到对象和属性,并对它们进行动画处理,一切都可以工作。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);

}

Michael Goldshteyn 13 年前

它是 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);
}