CRect rc;
GetClientRect(rc);
CImage myimage;
myimage.Create(rc.Width(), rc.Height(), 24);
CDC memdc;
memdc.CreateCompatibleDC(&dc);
CBitmap * pOldBitmap = memdc.SelectObject(CBitmap::FromHandle((HBITMAP)myimage));
memdc.BitBlt(0, 0, rc.Width(), rc.Height(), &dc, 0, 0, SRCCOPY);
memdc.SelectObject(pOldBitmap);
At this point your myimage
object should have a copy of what was painted on the dc
.