Question

I have a dynamic listbox and I’d like to add a dynamic validator control so that the user must select 2 options from the listbox – no more, no less. I’ve played around with the rangevalidator and the regularexpressionvalidator controls but they didn’t work.
Has anybody out there done this before?

Answer 1

A custom validator is fine…but the code is very simple:

Protected Sub myCustomVal(ByVal sender As Object, ByVal e As ServerValidateEventArgs)

   If ListBox1.GetSelectedIndices.Length =2 THEN
      e.isvalid = true
   Else
      e.isvalid = false
   end if

End Sub

You don’t actually need to traverse the list and evaluate all of the controls individually.