Printing the Form (Visual C#)

This example demonstrates printing a copy of the current form.
You may also use the PrintDocument component instead of PrintForm component with the same way.

This technique captures the gdi handler of the form and pastes it as image to the printer (as bitmap). It is not so good idea because the image has no good quality! If you plan to print photos and other material that requests high quality forget this technique and start to play drawing in the printer's canvas (i will show you in another post it is very easy).

Lest CODE!

[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();
   printDocument1.Print();
}

Compiling the Code

This example requires:

• A PrintDocument component named printDocument1 with a PrintPage event handler.
• A Button named printButton with a Click event handler.

The example code replaces the existing event handlers. The form is printed when printButton is clicked.

Robust Programming

The following conditions may cause an exception:

• You do not have permission to access the printer.
• You do not have permission to use unmanaged code.
• There is no printer installed.