Screen s = Screen.PrimaryScreen;
Bitmap bit = new Bitmap(s.Bounds.Width, s.Bounds.Height);
Graphics g = Graphics.FromImage(bit);
g.CopyFromScreen(new Point(0, 0), new Point(0, 0), bit.Size);
bit.Save("d:\\j.bmp");
原文：http://www.cnblogs.com/xh0626/p/5152826.html