CAPTURE ECRAN (SCREENSHOT)

// declaration de l'api P/Invoke 
// Ce code doit etre mis dans une class héritant de la classe Form
[DllImport("coredll.dll")]
public static extern int BitBlt(IntPtr hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, IntPtr hdcSrc, int nXSrc, int nYSrc, uint dwRop);

const int SRCCOPY = 0x00CC0020;

private void Snapshot(string fileName)
{
      Graphics gx = this.CreateGraphics();
      Rectangle rect = Screen.PrimaryScreen.Bounds;
      Bitmap bmp = new Bitmap(rect.Width, rect.Height);
      // Creation d'un objet graphics compatible 
      Graphics gxComp = Graphics.FromImage(bmp);
      // Prendre la photo
      BitBlt(gxComp.GetHdc(), 0, 0, rect.Width, rect.Height, gx.GetHdc(), rect.Left, rect.Top, SRCCOPY);
      // Enregistrement dans un fichier
      bmp.Save(fileName, System.Drawing.Imaging.ImageFormat.Bmp);
      // Cleanup
      bmp.Dispose();
      gxComp.Dispose();
}