I'm trying to add line numbers to rows in a RichEdit Control. To do that, I have to know when the scrollbar scrolls up and down, so I can align the line numbers accordingly. I have captured all arrow keys and subclassed the WM_VSCROLL message (which is triggered when you click the scrollbar). Leaves one problem: the mousewheel.

By subclassing the WM_MOUSEWHEEL message I can refill the line numbers when the mouse is scrolled. The problem, however, is that the WM_MOUSEWHEEL message is sent before the actual scrolling has been done. So my code refills the line numbers to the unchanged situation, and only then the contents of the RichEdit box are being scrolled. So my line numbers are always 'one scroll behind'.

Is there any message I can intercept that tells me when the contents have actually been scrolled? When the mousewheel has finished scrolling? And if not, is there a way to turn of smooth scrolling in Rich Edit controls?

Thanks for your help.