How to draw a dashed line in Windows Store (XAML) applications?
Use the StrokeDashArray property. For example, the following XAML creates a line in the image below:
<Line Stroke="Red" X1="0" X2="400" Y1="0" Y2="400" StrokeThickness="9" StrokeDashArray="3,5" StrokeDashCap="Round" />