is creating keypress event in propertygrid possible?

What I'm trying to do is this:

In the propertygrid, there are two properties (lets call them propA and propB). What I want it to do is when I input a character into propA, I want it to be copied IMMEDIATELY to propB. For each keypress, i want it to be copied into propB without having to change the focus. As I type into propA, it will be typing it into propB as well, basically.

I've tried ProcessKeyPreview, but the way I've coded it, anything I put in propB gets deleted. Perhaps there is a better way of coding? or different approach instead of ProcessKeyPreview?

Note: I've tried it with subclassing using NativeWindow, AND using win32 APIs, but no success.

The more logical approach would be to have the underlying object whose properties you're displaying do it.