Numbers or letters in a TextBox

[PABLIN]

How I can have a TextBox that to only lets me enter
letters or numbers?

 

[Dune]

stick a regular expression validator in to validate the
contents of the textbox and then set the
validationexpression property of the validator control to
allow only letters or numbers.

check out this link for info on regular expressions:

http://msdn.microsoft.com/library/default.asp?
url=/library/en-
us/cpgenref/html/cpconregularexpressionslanguageelements.as
p