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The LA Fox Developer Newsletter
March 1998
Visual FoxPro Components. Be forewarned — this is not a VFPonly 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 application 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 understand 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 performance 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 application 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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