[System.Runtime.InteropServices.DllImport("gdi32.dll")]
 public static extern long BitBlt (IntPtr hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, IntPtr hdcSrc, int nXSrc, int nYSrc, int dwRop);
 private Bitmap memoryImage;
 private void CaptureScreen()
 {
    Graphics mygraphics = this.CreateGraphics();
    Size s = this.Size;
    memoryImage = new Bitmap(s.Width, s.Height, mygraphics);
    Graphics memoryGraphics = Graphics.FromImage(memoryImage);
    IntPtr dc1 = mygraphics.GetHdc();
    IntPtr dc2 = memoryGraphics.GetHdc();
    BitBlt(dc2, 0, 0, this.ClientRectangle.Width, this.ClientRectangle.Height, dc1, 0, 0, 13369376);
    mygraphics.ReleaseHdc(dc1);
    memoryGraphics.ReleaseHdc(dc2);
 }
 private void printDocument1_PrintPage(System.Object sender, System.Drawing.Printing.PrintPageEventArgs e)
 {
    e.Graphics.DrawImage(memoryImage, 0, 0);
 }
 private void printButton_Click(System.Object sender, System.EventArgs e)
 {
    CaptureScreen();
    printPreviewDialog1.Show();
 }