The LA Fox Developer

A Newsletter for FoxPro Application Developers in Southern California

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October 1997

Automatic Combo Boxes

Out and About

By Todd Landrum, Rock Mountain Fox User Group

by Barry R. Lee

A combo box to pick one value out of many is something that is used in all applications. In many cases, the values for the combo box are also under the user’s control. With a little fore planning, you can make the process of creating a new combo box nearly automatic.

Let’s take as an example phone number types. If you’re going

to build a combo box for this it might contain Home, Office, and _______________________________________________ Cellular. Those are probably good choices but what if the user

wants to add Pager? Or they want to remove Home? Using the ___________ plan outlined below, we can handle this easily.

First, we start with a table that is going to hold our combo box values. I’m going to call this table zPopup. It has one field, zpuValue and 3 records: Home, Work, Cellular.

What if I need another combo box with other values? Do I want to create another table to hold those values? The simpler solution is to have one table that holds all of my combo box choices. We add a new field to zPopup called zpuKey.

Let’s say our second combo box is automobile types. We’ll give 3 values to get the user started (Chevy, Ford, Dodge) but they will be able to change the combo anyway they like. Our zPopup table would look like:

zpuKey	zpuValue
Phone	Home
Phone	Work
Phone	Office
Auto	Chevy
Auto	Ford
Auto	Dodge

Now let’s create a combo box control that can work with this table. Subclass VFP’s base combo box to a new combo box. Set the following properties:

RowSource	None
RowSourceType	3— SQL Statement
Style	2— Dropdown List
	(Con’t, page 3)

In this issue	Pop-ups w/Error Handling	Page 3
	Frameworks/Codebook	Page 5
	Why Visual MaxFrame Pro	Page 6

and much more!

The October meeting of LA Fox will be held on Oct. 20, 1997, at 7:30 PM at our regular meeting place (the Torrance Airport, 3301 Airport Drive, in Torrance). For details on how to get there, see the map on the back page.

At LA Fox

October 20, 1997, 7:30 PM - Peter Butterfield. Peter Butterfield’s Los Angeles consulting firm has built a nation-wide client list in a dozen business domains. He has been an xbase consultant so long that he still uses “ctrl+w”. His VFP framework, Butterworks, originated with the beta version VFP 3.0 in 1995, and is now in its third design iteration. Employing the user interface portion of Butterworks as a case study, he will discuss some of the issues of the object oriented design pro cess Among those topics covered will be the use of visual object modeling tools, the applicaton of design patterns, the management of class hierarchies, and, particularly, the non- visual approach to VFP implementation of object model designs.

November 17, 1997, 7:30 PM - Rick Strahl. Rick is President of West Wind Technologies, a company providing Internet-based application development using Visual FoxPro. Rick has been extensively involved in Web-based application development, and is author of Web Connection for Visual FoxPro, a tool that allows Visual FoxPro to be used as the back-end to build Web applications. Rick is frequently published in FoxPro-related magazines and books.

December 15, 1997,7:30 PM - Annual LA Fox Christmas Party. It’s coming up on that time of the year again. We’ll be having a White Elephant Gift Exchange again this year. As always, there’ll be plenty of tasty treats along with good cheer and fellowship. For complete details, see the article on page 9.

Elsewhere

November 17-21, 1997. Comdex ‘97, the big daddy of all

(Con’t, page 2)