In my form I have a dropdownlist for Country field and one textbox for ZipCode.
I want the zipcode textbox to be validated only if U.S.A is selected from the Countrydropdown list.
Can you help

There are a few ways to validate zip codes, the best one is to use the United States Postal Services API (www.usps.com) however, unless you are using USPS to ship something, they will not allow you to use their API.

Another component that I have used is Assisted Solutions CityState Finder (http://www.assistedsolutions.com/com...tyStateFinder/) this works very well but it is very picky about City State Zip code combonations. (For example if suburb A shares the same zip code a Town A, the component will bark at you that the name of suburb A does not match the zip code provided and you need to supply Town As name.)

"The one language all programmers understand is profanity."

You can use custom validator for the zip code text box.
http://samples.gotdotnet.com/quickst...on.aspx#custom

No, that wont work. The only thing a custom validator is going to do is verify that XXXXX are all numbers, which is fine, except that if i enter say 90210 and I say I am living in aspen, colorado while the custom validator would accept that value, it is not valid for the city and state i provided.

I think the OP is looking for a control that will validate the zip based on user entered city and state.

"The one language all programmers understand is profanity."

"I want the zipcode textbox to be validated only if U.S.A is selected from the Countrydropdown list. "
-From the above statement, I understand that the input and a numeric input should only be asked in the zipcode box, if country is USA. Custom validator can validate this.

I agree, custom validator cannot validate, if the entered zipcode is the right one for the city, without a US zipcode database.

Thank you very much for the information. I could make it work I wrote a javascript to validate the zipcode if it is for U.S.A.
Thanks