Need to know when a textbox is finished initializing/drawing itself

I need to know when a textbox is done doing everything it needs to do to make itself exist on a form. I am extending the textbox class and need to know when the textbox is ready to go and that I can start manipulating it. I tried catching the paint event but that didn't work. I would like something similiar to the form load event but haven't found an equivalent.

Thanks.

Tony