Home » Tip Bank » Database Development » Oracle

Language: SQL
Expertise: Beginner

Jul 23, 1997

Question:
I am developing a radon database for the Ohio Department of Health with Oracle Power Objects. I have two combo boxes. First a choice is made from one of them, and in the second one, the values change according to that choice. I know Microsoft Access and Developer 2000, but the logic used in them is not working here. What I am missing?

Also, I am not able to create the main menu to open all the forms from that form-Main Menu. Help!

Answer:
There are two logical steps to solve your problem. The first step is to understand how to populate the values in a list box. Whenever you change the value of the Translation property for a list box, the list box will repopulate itself.

The second step is to know when to repopulate the list box. The best method to use for this is the Validate() method. Validate() is called whenever a user changes a value in an object and leaves that object — just the time you want to repopulate the other list box. You should put code in the Validate() method for each of the list boxes to populate the other list box.

I have two cautions about using the Validate() method. First, you want to use the internal variable newval when setting the Translation property, since the value of newval, as the name implies, is the new value for the list box. Secondly, make sure you explicitly return True from the Validate() method, or else the focus will be sent back to the object and the new value replaced with the old value.