c#获取桌面,不包括本程序

[DllImport("gdi32.dll")]//在两个上下文中复制图像.
		private static extern long BitBlt (IntPtr hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, IntPtr hdcSrc, int nXSrc, int nYSrc, int dwRop);

		[DllImport("user32.dll")]//获取Desktop句柄
		private static extern IntPtr GetDesktopWindow();

		private PaintScreen()
		{
			//
			// TODO: 在此处添加构造函数逻辑
			//
		}

		//FileName:保存于指定的文件中.
		//Format:指定文件格式.如:jpeg bmp 等等
		public static void ps(string FileName,ImageFormat Format)//保存屏幕图像.
		{
			Bitmap MemoryImage;//在内存中保存屏幕图像.
			//获取屏幕的高度,宽度
			Size ScreenSize = new Size (Screen.PrimaryScreen .Bounds .Width,Screen.PrimaryScreen .Bounds .Height);

			IntPtr Desktop = GetDesktopWindow();//获取Desktop句柄
			Graphics Desktops = Graphics.FromHwnd (Desktop);//从句柄转换到图像对象.

			MemoryImage = new Bitmap(ScreenSize.Width ,ScreenSize.Height,Desktops);//创建一个同屏幕高,宽一样的位图对象
			Graphics MemoryGraphics = Graphics.FromImage(MemoryImage);//取得它的图像对象.

			IntPtr Src = Desktops.GetHdc();//取得桌面的HDC
			IntPtr Dest = MemoryGraphics.GetHdc();//取得内存位图的HDC
			BitBlt(Dest, 0, 0, ScreenSize.Width ,ScreenSize.Height,Src, 0, 0, 13369376);//进行复制
			Desktops.ReleaseHdc(Src);//必须释放
			MemoryGraphics.ReleaseHdc(Dest);//必须释放
			MemoryImage.Save (FileName,Format);//保存图像
		}