Validating listbox Freesexline
Validation checks to see if there is at least one selected item.
To validate for selected item of a listbox, just specify the ID of the listbox in the Control To Validate property of the Required Field Validator.
how do i check if an item is selected or not in my listbox?
Search for validating listbox:
You may want to go with the early-break out approach based on your prob desc & the fact that List Box.