为什么当我使用故事板时这些动画不起作用? [英] Why don't these animations work when I'm using a storyboard?

问题描述

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.它看起来像这样:

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

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，就像上面的代码那样，它就可以工作.但是如果我使用上面注释掉的代码，这实际上是可以想象的最简单的 Storyboard 创建代码，什么也不会发生.动画运行 - 至少会引发 Completed 事件 - 但屏幕上没有任何变化.

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.

显然我做错了什么，但我看不出是什么.我见过的每一个在代码中创建故事板的例子都是这样的.很明显，我还不知道关于动画和故事板的一些东西:它是什么?

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?

推荐答案

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/代码>.至少，这就是我在进行 Anvaka 建议的更改时遇到的非常令人困惑的异常的解释:

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:

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

似乎要为这些设置动画，我必须使用 NameScope 并使用 SetTargetName 来命名 TransformElement.然后，只要我将设置名称范围的 FrameworkElement 传递给 Begin 方法，故事板就可以找到对象和属性，并为它们设置动画等等作品.最终结果如下:

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:

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);

}

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