binding - UserControl.MouseEnter 在绑定中不起作用

Question

我的用户控件有样式：

 <Style x:Key="SlideControlGrid" TargetType="{x:Type UserControl}">
    <Style.Triggers>
        <EventTrigger RoutedEvent="UserControl.MouseEnter">
            <BeginStoryboard>
                <Storyboard>
                    <ColorAnimation Duration="00:00:00.2"
                                    From="#FFFFFFFF"
                                    Storyboard.TargetProperty="Background.Color"
                                    To="#FFFCEE" />
                </Storyboard>

            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="UserControl.MouseLeave">
            <BeginStoryboard>
                <Storyboard>
                    <ColorAnimation Duration="00:00:00.2"
                                    Storyboard.TargetProperty="Background.Color"
                                    To="#FFFFFFFF" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="UserControl.PreviewDragOver">
            <BeginStoryboard>
                <Storyboard>
                    <ColorAnimation Duration="00:00:00.05"
                                    Storyboard.TargetProperty="Background.Color"
                                    To="#FFD86C" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="UserControl.PreviewDragLeave">
            <BeginStoryboard>
                <Storyboard>
                    <ColorAnimation Duration="00:00:00.2"
                                    Storyboard.TargetProperty="Background.Color"
                                    To="#FFFFFFFF" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Style.Triggers>
</Style>

在我的用户控件中，我有矩形，并且在previewdragover期间，我想更改矩形的填充。这是我的矩形样式：

<Style x:Key="DragAnimation" TargetType="{x:Type Rectangle}">
    <Setter Property="Visibility" Value="Hidden" />
    <Style.Triggers>
        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}, Path=IsMouseOver}" Value="true">
            <DataTrigger.EnterActions>
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation Duration="0:0:0.1"
                                         From="0.2"
                                         Storyboard.TargetProperty="Opacity"
                                         To="1.0" />
                    </Storyboard>
                </BeginStoryboard>
            </DataTrigger.EnterActions>
            <Setter Property="Visibility" Value="Visible" />
        </DataTrigger>
    </Style.Triggers>
</Style>

当我使用ismouseover时，everythink 做得很好。当我使用usercontrol.previewdragover或previewdragover时，我的矩形不起作用。我做什么？