WM_PRINTCLIENT message

Hi,
Has anybody used WM_PRINTCLIENT message?
I m using the following SendMessage call....

SendMessage(hWnd, WM_PRINTCLIENT, (WPARAM) hDCMem, PRF_CLIENT | PRF_ERASEBKGND | PRF_CHILDREN );

here if i pass a control handle......then i get the correct bitmap.
but if i pass the form handle, it returns a black window.
Any clues?
Thanks,
peenu.
[380 byte] By [peenu] at [2007-11-18 8:41:32]