The LA Fox Developer Newsletter

March 1998

Visual FoxPro Components. Be forewarned — this is not a VFP-

only session. Significant time will be spent with other tools like

Visual Basic and Visual lnterDev. If you have been looking for an

introduction on how to use these tools with Visual FoxPro, this

is the session for you.

Integrating Tahoe with OfficeNBA

Have you ever wanted to add that special feature in your appli-

cation that acted like a spreadsheet or had time-keeping

capabilities? Tools like Excel, Outlook, and other applications

that support automationNBA can be incorporated into your

applications very easily. The key to success is in knowing

where to start and understanding the object models of the

various applications you wish to incorporate. Once you under-

stand the mechanics, then you can focus on how to use the

tools in conjunction with your application. This session will

discuss how and why you may want to incorporate VBA

components into your applications.

Mac Rubel

VFP Database Performance: An Evaluation

Visual FoxPro remains the its title of Desktop database perfor-

mance champion. Its speed in handling data sets from the small

to the very large is undisputed and something that we, as

FoxPro programmers have taken for granted for many years.

Have you ever wondered exactly what FoxPro’s performance

really was and what impact various hardware and programming

cjptinns have on application speed

continuing evaluation of factors that affect FoxPro performance.

We will discuss key selection strategy, RAM memory, User

Memory, operating system choice, disk speed, cache options,

local vs. remote data, client server access to tables and other

“late breaking news” for the latest versions of Visual FoxPro.

This session is a must for people concerned about optimizing

database performance.

Drew Speedie

Local/Parameterized Views As A Data-Entry Strategy Skill

Level: Intermediate

While local/parameterized views are handy for filtered combo!

listbox RowSources, reports, viewing read-only data, etc., the

fact that they are updatable makes them a powerful tool for

many common data-entry situations encountered in the typical

VFP application. You can easily handle all your data-entry

needs in views, yielding portability to client/server apps and

solving many common VFP data-entry issues at the same time.

In this session we’ll cover some fundamentals for achieving

success using updatable views and then demonstrate specific

techniques for handling data-entry via local parameterized views.

The demonstrations/examples concentrate on the following:

*

Use views to control when/how field rules fire.

*

Simplify data-entry of foreign keys by using views with

regular and outer joins.

*

Create and maintain views that include features beyond

the scope of the View Designer.

[Attendees should have experience creating data-entry forms.]

Turning an App Based On Local Views into a Client-

Server/Remote Data App

Skill Level: Intermediate

If you’ve been using local (parameterized) views for data-entry in

VFP applications based on a local VFP data store, you can

frequently “upsize” to a remote data back-end with a minimum

of hassle. This session is a practical demonstration of the

“prototype locally, deploy remotely” strategy marketed with the

introduction of views in VFP 3.0. The main demonstration in this

presentation starts with a data-entry form “pointing” to a local

VFP database and then shows the minimal modifications

necessary to allow it to use either the local VFP data or remote

SQL-Server data. A strategy for creating a client-server applica-

tion using one connection per user that allows using any

combination of remote views and SQL Pass-Thru cursors is

discussed and demonstrated. If you can create an application

using local views for data entry, you can leverage those same

techniques to go client-server!

[Attendees should have experience using buffering and local

views for data-entry forms, client-server fundamentals helpful.]

Subclassing (Con’t from page 8)

new class to your class library for each of these base classes.

Do as follows:

1.

Click the New Class button (the fifth button from the left on

the Class Browser screen).

7 Click the ased On combo box and move it to Container.

3.

Using the same naming convention you chose for your

subclassed check box, enter a name for this new class.

4.

The Store Infield should default to the path and name of your

visual class library. Click Ok.

5.

The Class Designer will appear and you will see one con-

tainer object in it.

6.

Close the Class Designer and the new class, based on the

VFP container base class will be added to your visual class

library.

7.

Repeat steps 1 —6 for each of the visual FoxPro base

classes, using the same naming convention (use this order:

shape, line, OLE bound control, page frame, timer, image,

grid, spinner, list box, combo box, check box, option

group, command group, command button, edit box, text

box, label)

When you are done creating your own subclassed versions of

the base classes, you can add them to the FoxPro development

environment as a toolbar. Do this by opening a form and

clicking on the View Classes button (second from the left on the

Forms Control toolbar). Click Add on the drop down menu and

select your VCX from the directory in which you saved it. The

standard Forms Control toolbar will be replaced by your newly

created visual class library and you can choose controls from it

and place them on a form. The controls you place will then be

based on your subclasses of the VFP base classes.

[Ed. Note: Russell Campbell is president and owner of The

Interthink Consulting Group, Inc. in Atlanta.]

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