I'm looking for some kind of form level event that I can hook/add/use
to tell me when ever some input control has changed its state. As a
hack currently I set KeyPreview to true and hooked the KeyPress event.
This works great for text boxes etc, but if a user uses the mouse to
select someting in a listbox it doesnt catch it of course.

The idea is something like this, in the even I want to check the state
of the inputs and enable disable for example the Save button. Delphi
had a neat way to do this with actionlist and I know there are free and
3P action lists for .NET, but this is an existing WinForms app and I
cant redo it. I just need a basic event I can hook to properly
enable/disable controls. The other "hack" option is a timer, but thats
pretty ugly too.

I've also considered hooking into the windows message pipe and ignoring
obvious ones like WM_Paint etc, but again I'd like to avoid this and
find something else. Anyone have any suggestions?