C#中如何对当前窗体进行打印预览

[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();

}