我可以使用自己的AttachedProperty作为StoryBoard.TargetProperty吗？

Question

一旦VisualState“Prepared”被激活，我视图中的一个控件应将AttachedProperty“FocusClaim”设置为true。 msdn文档说我可以使用AttachedProperties，我只需要在括号中给出ownerType和PropertyName。但这样做会导致异常： System.InvalidOperationException：无法为给定对象解析TargetProperty“（my：VisualStateMacro.FocusClaim）”。

那是带动画的VisualState：

<VisualState x:Name="Prepared">
    <Storyboard>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="Foo"
            Storyboard.TargetProperty="(my:VisualStateMacro.FocusClaim)">
            <DiscreteObjectKeyFrame KeyTime="0">
                <DiscreteObjectKeyFrame.Value>
                    <system:Boolean>True</system:Boolean>
                </DiscreteObjectKeyFrame.Value>
            </DiscreteObjectKeyFrame>
        </ObjectAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>

实际目标：     <TextBox my:VisualStateMacro.FocusClaim="False" x:Name="Foo"/>

一行（在MSdn上找到PropertyPath for Animation Targets）虽然与同一网站上给出的示例有些冲突：

  

propertyName必须是Storyboard.TargetName指定的类型上存在的属性。

还有几行：

<animation Storyboard.TargetProperty="(ownerType.propertyName)" .../>

我允许使用自己的AttachedProperty作为目标，还是我必须使用Control类中的属性？

这是我定义AttachedProperty的方式：

public class VisualStateMacro
{
    public static bool GetFocusClaim( DependencyObject obj )
    {
        return (bool) obj.GetValue( FocusClaimProperty );
    }

    public static void SetFocusClaim( DependencyObject obj, bool value )
    {
        obj.SetValue( FocusClaimProperty, value );
    }

    public static readonly DependencyProperty FocusClaimProperty =
        DependencyProperty.RegisterAttached( "FocusClaim", typeof( bool ),
                    typeof( VisualStateMacro ),
                    new PropertyMetadata( false, HandleFocusClaimChanged ) );

    private static void HandleFocusClaimChanged(
              DependencyObject d,
              DependencyPropertyChangedEventArgs e)
    {
        var focusTarget = d as Control;
        if(focusTarget==null)return;

        var shouldReceiveFocusNow = (bool)e.NewValue;

        if (shouldReceiveFocusNow)
        {
            focusTarget.Focus();
        }
    }
}