>Hi Jeffrey,
>In the refresh method of the button test the value of the text box. If it conforms to what you want, enable the push button - otherwise disable it.

Or just use the VALID of the textbox and WHEN of the command button to evaluate the status. You can return .F. in the When to disallow selection of the item and update it's Enable state - the only time that the command button's Enable needs to be evaluated is when you leave the textbox if it starts empty and the command button disabled; the only time the state of the command button changes is when the content is updated, which is checked by VALID whenever it's had Focus and the content altered.