为什么这些动画在我使用故事板的时候不工作?

I've created a simple subclass of StackPanel that I can move around on the screen using an animated TranslateTransform. It looks like this:

我创建了一个简单的StackPanel子类，我可以使用一个动画的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.");
    }
} 

And here is my problem: If I animate the X and Y properties directly, as the code above does, it works. But if I use the commented-out code above it, which is really the simplest creation of a Storyboard in code imaginable, nothing happens. The animation runs - at least, the Completed event gets raised - but nothing changes on the screen.

这是我的问题:如果我把X和Y的属性直接激活，正如上面的代码所做的那样，它是有效的。但是，如果我使用上面的注释代码，这实际上是可以想象的代码中最简单的创建故事板，什么都不会发生。动画运行-至少，完成的事件被提高-但没有任何改变在屏幕上。

Clearly I'm doing something wrong, but I can't see what it is. Every example of creating storyboards in code I've seen looks just like this. There's obviously something about animations and storyboards that I don't know yet: what is it?

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

2 个解决方案

#1

As it turns out, you can't use property path syntax in this case, because the properties being animated aren't properties of a FrameworkElement. At least, that's how I interpret the remarkably bewildering exception that I get when I make the change that Anvaka suggested:

事实证明，在这种情况下，您不能使用属性路径语法，因为动画的属性不是FrameworkElement的属性。至少，这就是我理解Anvaka提出的变化时所得到的异常令人困惑的异常:

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

To animate those, it seems, I have to use a NameScope and use SetTargetName to name the TransformElement. Then, as long as I pass the FrameworkElement that I set the name scope on to the Begin method, the storyboard can find the object and the properties and animate them and it all works. The end result looks like this:

为了使这些看起来有动画效果，我不得不使用一个命名库，并使用SetTargetName来命名TransformElement。然后，只要我通过将名称范围设置为Begin方法的FrameworkElement，故事板就能找到对象和属性，并对它们进行动画和动画。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);

}

#2

It's property path syntax. The following approach works:

它的属性路径语法。以下方式是:

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);
}