//屏幕宽
            int iWidth = Screen.PrimaryScreen.Bounds.Width;
            //屏幕高
            int iHeight = Screen.PrimaryScreen.Bounds.Height;
            //按照屏幕宽高创建位图
            Image img = new Bitmap(iWidth, iHeight);
            //从一个继承自Image类的对象中创建Graphics对象
            Graphics gc = Graphics.FromImage(img);
            //抓屏并拷贝到myimage里
            gc.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(iWidth, iHeight));
            //this.BackgroundImage = img;
            //保存位图
            img.Save(@"C:\" + Guid.NewGuid().ToString() + ".jpg");

C# 实现屏幕截屏