public static void SetBackgroundSource(this Grid grid, string url, RenderContext context)
 {
     if (string.IsNullOrWhiteSpace(url))
     {
         return;
     }
     grid.Background = new ImageBrush(context.ResolveImageSource(url));
 }
 public static void SetSource(this System.Windows.Controls.Image image, string url, RenderContext context)
 {
     if (string.IsNullOrWhiteSpace(url))
     {
         return;
     }
     image.Source = context.ResolveImageSource(url);
 }