有点麻烦。你可以搜一下UpdateLayeredWindow。使用WIN32的api来实现。
[DllImport("user32.dll", ExactSpelling = true, SetLastError = true)]
public static extern int UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags)... |