當我使用故事板時，爲什麼這些動畫不起作用？

Question

我創建了一個簡單的子類StackPanel，我可以使用動畫TranslateTransform在屏幕上移動。它看起來像這樣：

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."); 
    } 
} 

這裏是我的問題：如果我直接動畫X和Y屬性，如上面的代碼呢，它的工作原理。但是，如果我使用上面的註釋代碼，這是代碼中最簡單的創建代碼Storyboard，則什麼也不會發生。動畫運行 - 至少，Completed事件被提升 - 但屏幕上沒有任何變化。

顯然我做錯了什麼，但我看不到它是什麼。在我看到的代碼中創建故事板的每個示例都與此類似。顯然還有一些我還不知道的動畫和故事板：它是什麼？

Answer 1

事實證明，你不能在這種情況下使用屬性路徑語法，因爲屬性被動畫不是FrameworkElement的性質。至少，這就是我如何解釋顯着撲朔迷離的例外，我得到的，當我作出這樣的Anvaka建議的變化：

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

要動態的，現在看來，我必須使用一個NameScope和使用SetTargetName命名TransformElement 。然後，只要我通過FrameworkElement，我將名稱範圍設置爲Begin方法，故事板就可以找到對象和屬性併爲它們設置動畫，並且它們都可以工作。最終結果如下所示：

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

這是property path語法。以下方法適用：

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); 
}