asp.net required field validator for at least one textbox contains text

Question

I have three textboxes on an asp.net webform, how/can I use a required field validator to ensure that at least one of them contains text?

Answer 1

I would use a CustomFieldValidator like this:

and then in your codebehind you have:

protected void MyCustomValidator_ServerValidate(object source, ServerValidateEventArgs args)
{
     if (/* one of three textboxes has text*/)
         args.IsValid = true;
     else
         args.IsValid = false;
}

You can also add a Client-side component to this validation, and make it sexy by extending it with AJAX toolkit's ValidatorCalloutExtender control.