How to accomplish the "OnEraseBkgnd(CDC* pDC)" equivalent without MFC?

Win32API gives you DialogProc, which only allows you to return TRUE or FALSE, I cannot call a default dialogproc, then do something, then return.

overriding WM_ERASEBKGND to perform a ExcludeClipRect on a control does not work for me...
but it did in MFC.

any ideas anyone?