Can't see stroke - wpf

Question

I derive from shape, this is what is in the DefiningGeometry
protected override Geometry DefiningGeometry
{
get
{
topLeft.X = Math.Min(Start.X, End.X);
topLeft.Y = Math.Min(Start.Y, End.Y);
width.X = Math.Abs(Start.X - End.X);
width.Y = Math.Abs(Start.Y - End.Y);
rectBounds.X = topLeft.X;
rectBounds.Y = topLeft.Y;
rectBounds.Width = width.X;
rectBounds.Height = width.Y;
rectGeo.Rect = rectBounds;
return rectGeo;
}
}
I see the fill, but not the stroke, since the sroke is additional to the width and height I tried to make some room for it by setting:
Width = width.X + StrokeThickness;
//same for height.
But then nothing gets drawn, does anyone know what I am doing wrong? By the way the background and the stroke brush are different color.

Answer 1

Stroke is always on top of Fill. Thicknesses below 1.0 are no problem at all, although very thin strokes naturally tend to become invisible.
Fill exactly fills the Shape's geometry. Stroke renders the geometry's outline, half of the stroke lying inside, half outside the shape.
Never add StrokeThickness to your Shape's width (which would only work as you expect on rectangles anyway). See the MSDN for how the Shape's properties behave.
Do not derive from Shape to create simple geometric objects. Use the predefined Rectangle, Ellipse, Line etc. Use Path for more complex geometries and set Path.Data.
Also consult the Shapes and Basic Drawing in WPF Overview and maybe the Geometry Overview in the MSDN.

Answer 2

StrokeThickness for some reason should be larger than 1 (I am guessing the Fill brush is covering it), or don't set the Fill property, and StrokeThickness 1 works.