<Border BorderThickness="{Binding ElementName=mediaItemList,Path=HasItems,
Converter={StaticResource booleanToThicknessConverter}}">
<Border.BorderBrush>
<DrawingBrush Viewport="0,0,2,2" ViewportUnits="Absolute" TileMode="Tile">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="Black">
<GeometryDrawing.Geometry>
<GeometryGroup>
<RectangleGeometry Rect="0,0,50,50" />
<RectangleGeometry Rect="50,50,50,50" />
</GeometryGroup>
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Border.BorderBrush>
----other control content---------
</Border>