I have a payment screen and when the pmt type is not credit card, I want to prevent entry to the credit card textbox. How can I prevent the credit card textbox from receiving the focus at the time the user is entering the credit card field? I can't assume they'll only access it by tabbing there from the pmt type window, so I need to handle it when they're trying to enter the field. Pretty much like the FoxPro WHEN clause does. Is there somewhere I can return False to prevent the control taking focus?

I don't want to use the enabled property for this because that would require fiddling with it every time the record changed.

Thanks.