WPF:如何在Canvas中安装拇指行为?

<UserControl.Resources>
    <ControlTemplate x:Key="Transparent">
        <Rectangle Fill="Transparent"/>
    </ControlTemplate>
    <ControlTemplate x:Key="ThumbCanvas" TargetType="{x:Type Canvas}">
        <Grid>
            <Thumb x:Name="CanvasThumb" Template="{StaticResource Transparent}" DragDelta="CanvasThumb_DragDelta"/>
            <ContentPresenter Content="{TemplateBinding Content}"/>
            <!--error MC3011: Cannot find the static member 'ContentProperty' on the type 'Canvas'.-->
        </Grid>
    </ControlTemplate>
</UserControl.Resources>