validation for TEXTBOX

Question

hi,

      -> I am having the Text Box outside of the gridview

using that textbox adding the value in gridview

      -> How to validate the textbox without using Required Field Validator

bcz i am using another textbox inside the gridview for that textbox

i had given the  Required Field Validator,

     -> Actually, I am getting the problem if i am using two Required Field Validator for two Textbox the both textbox is affected

 

Please Help