You could check for
(empty(thisform.Text1.Text) and empty(thisform.Text2.Text) in the list click event or other approppriate event
Also you may make list enabled/disabled in the text1 and text2 valid events and set focus to another textbox if needed

>I have a form with 2 text boxes namely text1 and text2 and 2 list boxes namely List1 and List2. I have a button on a form that runs an SQL query. When I click on the button I would like to test whether there has been information added into these controls. For example if somebody inserts info into Text1 and selects items in List1 I would like to display a messagebox saying "You have not selected "Label for Text2" and "Label for List2" - Please try again"
>
>Thankyou