>Did you mean:
>

>string selValue = this.lsbUsers.SelectedItem.ToString();
>

>
>(note the parenthesis)
>
>or more probably:
>
>

>string selValue = this.lsbUsers.SelectedItem.Text.ToString();
>

Hi Paul,

I actually don't like the fact the check is done on the server (it then shows a label, which stays here).

I think the checking selected something is selected should be done from the client rather. It would be a bit of a challenge for me to write this JavaScript code, but hopefully I would manage.