后台用代码设置color

纯色：

SolidColorBrush brush = new SolidColorBrush(Colors.White);
window1.Background = brush;

渐变色：

LinearGradientBrush buttonBrush = new LinearGradientBrush(); 
buttonBrush.StartPoint = new Point(0, 0.5); 
buttonBrush.EndPoint = new Point(1, 0.5); 
buttonBrush.GradientStops.Add(new GradientStop(Colors.Green, 0)); 
buttonBrush.GradientStops.Add(new GradientStop(Colors.White, 0.9)); 

图片：

textBlock1.Background = new ImageBrush(new BitmapImage(new Uri(@"../Image/Bg.png", UriKind.RelativeOrAbsolute)));

如何将图片 设置为窗体的背景：

System.Drawing.Bitmap bitmap = global::WpfApplication1.Properties.Resources.bg;
ImageSourceConverter convert = new ImageSourceConverter();
System.IO.MemoryStream ms = new System.IO.MemoryStream();
bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
ImageBrush b = new ImageBrush();
b.ImageSource = (ImageSource)convert.ConvertFrom(ms);
this.Background = b; 

转载自：http://www.verydemo.com/demo_c134_i25143.html