private void button1_Click(object sender, EventArgs e) 
{ 
   Image pic = new Bitmap(this.Width, this.Height); 
   Graphics graphic = Graphics.FromImage(pic); 
   graphic.CopyFromScreen(new Point(this.Location.X, this.Location.Y), new Point(0, 0), new Size(this.Width, this.Height)); 
   pic.Save(@"d:/test.jpeg", ImageFormat.Jpeg); 
   graphic.Dispose(); 
} 

[System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")] 
private static extern bool BitBlt( 
   IntPtr hdcDest, //目標設備的句柄 
   int nXDest, // 目標對象的左上角的X坐標 
   int nYDest, // 目標對象的左上角的X坐標 
   int nWidth, // 目標對象的矩形的寬度 
   int nHeight, // 目標對象的矩形的長度 
   IntPtr hdcSrc, // 源設備的句柄 
   int nXSrc, // 源對象的左上角的X坐標 
   int nYSrc, // 源對象的左上角的X坐標 
   System.Int32 dwRop // 光柵的操作值 
   ); 
[System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")] 
private static extern IntPtr CreateDC( 
   string lpszDriver, // 驅動名稱 
   string lpszDevice, // 設備名稱 
   string lpszOutput, // 無用，可以設定位"NULL" 
   IntPtr lpInitData // 任意的打印機數據 
   ); 

private void Form1_SizeChanged(object sender, EventArgs e) 
{ 
  
} 

private void button2_Click(object sender, EventArgs e) 
{ 
   this.Hide(); 
    
   IntPtr dc1 = CreateDC("DISPLAY", null, 
       null, (IntPtr)null); 
   //創建顯示器的DC 
   Graphics g1 = Graphics.FromHdc(dc1); 
   //由一個指定設備的句柄創建一個新的Graphics對象 
   Bitmap MyImage = 
       new Bitmap(Screen.PrimaryScreen.Bounds.Width, 
    Screen.PrimaryScreen.Bounds.Height, g1); 
   //根據屏幕大小創建一個與之相同大小的Bitmap對象 
   Graphics g2 = Graphics.FromImage(MyImage); 
   //獲得屏幕的句柄 
   IntPtr dc3 = g1.GetHdc(); 
   //獲得位圖的句柄 
   IntPtr dc2 = g2.GetHdc(); 
   //把當前屏幕捕獲到位圖對象中 
   BitBlt(dc2, 0, 0, Screen.PrimaryScreen.Bounds.Width, 
       Screen.PrimaryScreen.Bounds.Height, 
       dc3, 0, 0, 13369376); 
   //把當前屏幕拷貝到位圖中 
   g1.ReleaseHdc(dc3); 
   //釋放屏幕句柄 
   g2.ReleaseHdc(dc2); 
   //釋放位圖句柄 

   Bitmap img = new Bitmap(MyImage, 800, 600); 
   //縮放圖片到800*600 
   img.Save("d://MyJpeg.jpg", ImageFormat.Jpeg); 
   MessageBox.Show("已經把當前屏幕保存到" + 
       "C://MyJpeg.jpg文件中！"); 
   this.Show(); 
}