WPF Window Background ImageBrush not tiling

Question

I have a window with a background image. The image may change at runtime which really should not matter for this.

I want the image to be fixed to the top left (which it

Answer 1

If you would like the entire solution in c#

ImageBrush brush = new ImageBrush();
brush.ImageSource = new BitmapImage(new Uri(@"c:\your\image\source.gif"));
brush.TileMode = TileMode.Tile;
brush.ViewportUnits = BrushMappingMode.Absolute;
brush.Viewport = new Rect(0, 0, brush.ImageSource.Width, brush.ImageSource.Height);

MainWindow1.Background = brush;