WPF Rectangle draw border

Go to Properties -> Brush -> Stroke and select the border-related information:

enter image description here

Also in the Properties -> Appearance section you can do additional customizations over the border/stroke.

Looks like you can do it with a Rectangle, if you set the Height to 1 and then vertically align it to the bottom like so:

<Rectangle Height="1" Stroke="Red" StrokeDashArray="1 2" VerticalAlignment="Bottom" />

Related