如果使用.NET 2.0（或更高版本）框架，则可以使用
CopyFromScreen()此处详细介绍的方法：
http://www.geekpedia.com/tutorial181_Capturing-screenshots-using-
Csharp.html
//Create a new bitmap.var bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);// Create a graphics object from the bitmap.var gfxScreenshot = Graphics.FromImage(bmpScreenshot);// Take the screenshot from the upper left corner to the right bottom corner.gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);// Save the screenshot to the specified path that the user has chosen.bmpScreenshot.Save("Screenshot.png", ImageFormat.Png);
