如何使用xaml中的样式在画布上移动椭圆

<Canvas>
    <Ellipse Width="50" Height="50" Fill="Blue" Style="{StaticResource MovingEllipseStyle}" />
</Canvas>

<Canvas.Resources>
    <Style x:Key="MovingEllipseStyle" TargetType="Ellipse">
        <Setter Property="Canvas.Left" Value="0" />
        <Setter Property="Canvas.Top" Value="0" />
        <Setter Property="RenderTransformOrigin" Value="0.5,0.5" />
        <Setter Property="RenderTransform">
            <Setter.Value>
                <TranslateTransform />
            </Setter.Value>
        </Setter>
        <Style.Triggers>
            <EventTrigger RoutedEvent="Loaded">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation Storyboard.TargetProperty="(Canvas.Left)" From="0" To="200" Duration="0:0:2" RepeatBehavior="Forever" AutoReverse="True" />
                        <DoubleAnimation Storyboard.TargetProperty="(Canvas.Top)" From="0" To="200" Duration="0:0:2" RepeatBehavior="Forever" AutoReverse="True" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Style.Triggers>
    </Style>
</Canvas.Resources>