pinvoke.net: Edit: user32.printwindow

@msdn=http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/prntspol_6qpj.asp
@pinvoke=http://pinvoke.net/$$$.htm

Summary: The PrintWindow function copies a visual window into the specified device context (DC), typically a printer DC.

!!!!C# Signature:
   [DllImport("user32.dll", SetLastError = true)]
   [return: MarshalAs(UnmanagedType.Bool)]
   static extern bool PrintWindow(IntPtr hwnd, IntPtr hDC, uint nFlags);

!!!!VB Signature:
 <DllImport("user32.dll", SetLastError:=True)> _
 Private Shared Function PrintWindow(ByVal hwnd As IntPtr, ByVal hDC As IntPtr, ByVal nFlags As UInteger) As Boolean
 End Function

!!!!User-Defined Types:
None.

!!!!Notes:
This function is only available on Windows XP or higher. Windows 2000/9x/ME do not support it.

!!!!Tips & Tricks:
To capture only the client area of window, use PW_CLIENTONLY = 0x1 as nFlags

!!!!Sample Code:
Screenshotting a form to a Bitmap in C#:
 Graphics g = form.CreateGraphics();
 Bitmap bmp = new Bitmap(form.Size.Width, form.Size.Height, g);
 Graphics memoryGraphics = Graphics.FromImage(bmp);
 IntPtr dc = memoryGraphics.GetHdc();
 bool success = PrintWindow(form.Handle, dc, 0);
 memoryGraphics.ReleaseHdc(dc);
 // bmp now contains the screenshot

Me.AutoRedraw = True
 PrintWindow Me.hWnd, Me.hDC, 0

!!!!Alternative Managed API:
Control.DrawToBitmap()
Or call Control.InvokePaintBackground() followed by Control.InvokePaint().

The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a 
class ManagedWinapi.SystemWindow that has a Image property

Documentation: PrintWindow@msdn on MSDN