当我滚动滚动视图时，我在画布中的控制存在差距

Question

<Canvas DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" 
                SnapsToDevicePixels="True">
    <Path Data="{Binding PathGeometry}" 
          SnapsToDevicePixels="True"
          Stroke="{Binding Stroke}"
          StrokeDashArray="{Binding StrokeDashArray}"
          StrokeEndLineCap="Flat"
          StrokeLineJoin="Miter"
          StrokeMiterLimit="10"
          StrokeStartLineCap="Flat"
          StrokeThickness="{Binding StrokeThikness}"/>
    <Path Data="{Binding PathGeometry}"
          SnapsToDevicePixels="True"
          Stroke="Transparent"
          StrokeThickness="8" />

当我将滚动滚动到底部时，路径的高度会更高，但属性值不会更改。