The LA Fox Developer

A Newsletter for FoxPro Application Developers in Southern California

Visit our WebSite at: http://www.mesllc.com/lafox.html

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 frame-

work, 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 de-

signs.

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)