You can use the built in validator controls.
Here's more info and some examples:
I hope this helps,
Steve C. Orr, MCSD
"Yuriy" <yleyfmanhotmail.com> wrote in message
news:026601c35864$5c33ac10$a401280aphx.gbl...> Hello! I need to validate a date of birth, age, credit
> card, primary language etc. I found a couple example in
> the books but they are written not professinal. Thank you
> for evrything.