Microsoft Visual FoxPro
Moving from FoxPro 2.x to Visual FoxPro 5.0

Susan Graham, Microsoft Corporation July, 1997


Microsoft Visual FoxPro 5.0 is a powerful tool for creating state-of-the-art database applications. It provides support for the latest 32-bit Windows platform enhancements, high-performance client/server connectivity, a highly productive object-oriented design paradigm, extensive debugging capabilities, support for n-tier and Internet-enabled applications, and much more.

Visual FoxPro 5.0 can run most FoxPro 2.x applications with just a simple recompile. However, to take full advantage of the new features in their existing applications, developers will need to convert FoxPro 2.x code to the new object-oriented programming paradigm.

The purpose of this paper is to help FoxPro developers understand the issues involved with converting their existing applications. We will present three approaches to converting your applications, and provide detailed information about the conversion process. Applying the information in this paper to your specific applications will help you make informed decisions about whether to simply run existing applications under Visual FoxPro 5.0, or to convert them to the new paradigm.

Convert or Rewrite?

If it ain’t broke…

If your FoxPro 2.x application has been running well — it’s been through several versions, it’s stable, and needs no new functionality —there probably are few reasons to take the time and effort to migrate that application to Visual FoxPro. However, since the reality of most development projects is that they are never really finished, you need to consider the costs and benefits of the conversion process to determine which of the three recommended approaches is right for your application.

OK, it ain’t broke, but…

You want to move your applications into Visual FoxPro so that you can begin to take advantage of OOP, the new development environment, and the new database features of Visual FoxPro 5.0.

Most FoxPro version 2.x programs coded in traditional procedural style will run with minor modifications in Visual FoxPro. Conversion is a viable option for some developers.

For some developers, the question of how to migrate their applications forward includes the decision of whether or not to adopt the object-oriented programming style. While OOP is generally considered to be an extremely efficient approach to development, it does require a learning curve and an investment in reusable code libraries. It is very important to understand that using the simplest approach described here for running your existing applications under Visual FoxPro 5.0 does not require learning OOP.

Issues to consider

Here are some issues to consider when deciding how to migrate your application:

  • Can you take advantage of the built-in conversion tools? If you used the FoxPro Power Tools (Screen Builder) to create your FoxPro 2.x screens, then conversion is more automated, and you can choose any of the three approaches listed in the table below. If you did not use the Power Tools, then you can choose either the Minimalist or Rewrite option in the table below.

  • Does your application use FLLs (Fox Link Libraries, C-language extensions to FoxPro 2.x applications)? If so, do you have the resources (source code, development language of the FLLs) to recompile them to run as 32-bit extensions under Visual FoxPro 5.0?

  • Most third-party tools used by FoxPro 2.x developers are either available for Visual FoxPro 5.0, or their functionality has now been incorporated into Visual FoxPro. If you are using third party tools, you should consider how their functionality will be achieved under 5.0.

  • Is your application cross platform to Windows 3.1x, MS-DOS®, Unix, or Macintosh? Does it need to continue to be? Visual FoxPro supports those platforms when connected to an Internet server, but your applications need to be updated to support this architecture. Visual FoxPro 5.0 is only available for 32-bit Windows (Windows 95 and Windows NT 3.51 or higher).

  • Are you interested in updating your application with the Windows 95 standard interface? Two of the approaches described below give your applications a Windows 95 standard interface. One does not. This may be a consideration.


To migrate your application from FoxPro 2.x to Visual FoxPro, there are three basic approaches:




Minimalist - Compile and run - no conversion

  • Least amount of work to get apps running in 5.0

  • No further development time and effort
  • FP 2.6 architecture, doesn’t use VFP object model or event model

  • Old User Interface, not Windows 95 UI

  • Cost of maintenance/ improvement may be high

Hybrid - Convert and modify

  • Old code still usable

  • Uses VFP object model and event model

  • Begin to take advantage of new OOP functionality

  • Take advantage of new VFP 5.0 functionality

  • UI gets new look and feel (end user sees a difference)
  • Mix of 2.6 and 5.0 paradigms

  • Need to learn VFP object model and event model

  • More difficult to maintain


  • More powerful design tools

  • Database engine enhancements (Database Container with rules, triggers, referential integrity, etc.)

  • Tap the power of VFP 5.0, such as event handling, common code syntax, and benefits associated with OOP
  • OOP learning curve

  • Re-architect your application

  • Investment of time and money

Approach 1 Minimalist - Compile and run - no conversion

Your existing FoxPro 2.6 application should compile and run with few problems if you follow these steps:

  1. Create a new project in Visual FoxPro 5.0.

  2. Add your main PRG. (Note: Do not use an SCX as your main program. If you do, Visual FoxPro 5.0 will invoke the Converter.)

  3. Build the project.

  4. Add files not pulled in by the Project Manager (bitmaps, #includes, etc.).

  5. Build your application.

Using this minimal approach allows you to continue running mission critical applications as you take the time to learn the Visual FoxPro object and event models.

Approach 2 Hybrid - Convert and modify

This approach uses the Visual FoxPro 5.0 Converter to "migrate" your 2.6 screen sets to backwardly compatible Visual FoxPro form sets (as opposed to New Event Model form sets). Once screens are converted, continue the conversion so they become "true" Visual FoxPro forms that are able to use the new event model and other features. More on this later.

Converting FoxPro 2.6 Projects

Converting from the project level is generally the most desirable way to convert an application. Converting a project handles everything at once and is the only way to change screen sets into Visual FoxPro form sets, preserving the relationship between multiple FoxPro 2.6 screens. The alternative would be to convert individual screens, reports, etc. one at a time. This has the advantage of letting you move the process along more carefully. It also makes it possible to selectively convert some screens with the Visual conversion, and others with the Functional conversion (see below).

If you have used the Power Tools in FoxPro 2.6, the following FoxPro file types will convert automatically:

Reports created with the MS-DOS version of FoxPro do not need to be converted.  (These reports cannot be edited in either in FoxPro 2.6 for Windows or Visual FoxPro.)

Printer drivers are now managed by Windows. can be recompiled and run, but Visual FoxPro will not support these printer drivers.

Take note of the new functionality of the REPORT FORM command. See the Help file for REPORT FORM…ASCII and REPORT FORM…PREVIEW.

The application is responsible for converting your 2.6 code and objects to run under Visual FoxPro. It is installed by default in the Visual FoxPro home directory. The source code for the compiler is found in the \VFP\Tools\Convert directory. You can customize it for your particular needs, by setting the system variable _CONVERTER to your version of the

When you modify a 2.6 screen or project, Visual FoxPro 5.0 detects the older version and automatically loads and displays this screen:

Visual FoxPro Converter

Even though there is an option to save backup files in a directory named "Old", it is a better idea to work on a copy of your original 2.6 files rather than using the \Old directory. The primary reason for this is the path issues that occur when the directory structure is changed.

Choosing the Functional or Visual Conversion Method

One of the options you select in the Visual FoxPro 5.0 Converter (see the screenshot above) is Functional conversion or Visual conversion. It is very important to understand the differences between these two conversion methods.

The Functional conversion makes it easier for the developer in the short run, but can require more work to take advantage of the new features of Visual FoxPro 5.0. The Converter makes forms backward compatible, with attributes unique to this type of form (more later).

The Visual Conversion duplicates in Visual FoxPro 5.0 all visual components of a project (forms, buttons, and so on), but none of your existing snippet code (Open, Valid, etc.). All the code from the original FoxPro 2.6 snippets is copied to a non-compilable .prg file. It will then be your responsibility to cut and paste your procedural code into the appropriate events and methods of the new forms.

If you choose Functional conversion, the conversion process performs these steps:

  1. Copies the original project files to a new subdirectory named Oldx in the original .pjx directory and automatically increments x as you convert more projects.

  2. Converts the project and all associated screens, reports, and labels to Visual FoxPro format. New forms have the .scx and .sct extensions. Original files are given .s2x and .s2t extensions.

  3. Moves code snippets to appropriate event and method code.

The following table summarizes how 2.6 screen events are converted to VFP 5.0.

FoxPro 2.6 screen event

Converted Visual FoxPro 5.0 event

Setup - #Section 1


Setup - #Section 2



Form.Activate & FomSet.Activate










FormSet.Unload & SPR for procs/functions

The READ keywords CYCLE, LOCK, MOUSE, SAVE, and TIMEOUT are moved to FormSet properties with the names ReadCycle, ReadLock, ReadMouse, ReadSave, and ReadTimeout.

Form Sets and Control Properties

During Functional conversion, the Converter creates a file with an .spr extension for each converted screen. This file is different from a FoxPro 2.6 .spr file. In FoxPro 2.x, the .spr file was generated code based on what was found in the .scx. In Visual FoxPro, the .spr file is a “wrapper” file that includes the correct DO FORM command required to run the screen code. Here is an example of the .spr created after converting Laser.scx from the FoxPro 2.6 samples:

*- [CONVERTER] Declare arrays

*- [CONVERTER] Declare variables for record pointers
PUBLIC _iconvLaserGoToPlaceHolder


DO FORM "laser.scx" NAME _RH21148KX LINKED 

*- [CONVERTER] Begin CLEANUP and other procedures from 2.x Form

PROCEDURE setltags
DIMENSION flds(256), ltags(256)
ltags(1) = "Record#"
FOR i = 2 TO 256
    IF LEN(TAG(i-1)) = 0
        i = i - 1
        DIMENSION ltags(i)
        ltags(i) = TAG(i-1)
ord = "TITLE"

*- [CONVERTER] End CLEANUP and other procedures from 2.x Form

Using the DO FORM Command

The DO FORM command has two very useful clauses: NAME and LINKED. These clauses are useful because they enable you to use your unchanged 2.6 code and add 5.0 object features, by providing an object reference to the form. The NAME clause specifies a variable or array element with which you can reference the form or form set. If you specify a variable that doesn’t exist, Visual FoxPro automatically creates it. When you specify an array element, the array must exist before you issue DO FORM. If the variable or array element you specify already exists, its contents are overwritten.

If you omit the NAME clause, Visual FoxPro creates an object type variable with the same name as the form or form set file.

Include LINKED to link the form to the variable associated with it so that the form is released when the variable goes out of scope. If you don’t include LINKED, a form can still be active, even though there is no object variable associated with the form.

The Converter places these files in the following locations in the Project Manager.

FoxPro 2.6 files

Project Manager tab

.prg and .spr files

Code tab

.scx and .sct files

Documents tab

.frx and .lbx files

Documents tab

In the Functional conversion, each converted form is in FoxPro 2.6 READ-compatibility mode. Each form set contains one page frame that contains one page for each read level of the original screen. This format accounts for any and all READ LEVELS your FoxPro 2.6 code might have.

The WindowType Property

The FormSet WindowType property identifies the READ compatibility mode of converted forms. If forms are in READ compatibility mode, the WindowType property is either 2 (Read) or 3 (Read Modal), and the form set takes on the READ qualities of a 2.6 screen set. Execution stops when a DO FORM or SHOW command calls the form.

The WindowType properties that relate to 2.6 screen compatibility are only available with Functionally converted 2.6 screens. When screens are converted Visually or are created in Visual FoxPro, this WindowType property only relates to standard Visual FoxPro modeless and modal behavior and cannot be set to 2 and 3. The only time you will see form set WindowType properties with READ capabilities is in a Functionally converted form set.

Variable Scoping in Load Events

In FoxPro 2.6 READ compatibility mode, variables created in the Load event of a form set with WindowType set to 2 or 3 are scoped to the form set and visible to the entire form set, its forms, and its controls. You can control the visibility of variables created in other form set events or methods by using the PRIVATE, PUBLIC, or LOCAL commands.

Environmental settings are automatically defined in the form set Load event and the current record pointers are saved in public variables during the form set Unload event. The data environment of the form is updated with all appropriate FoxPro 2.6 view environment objects, such as the table aliases, index orders, and relationships. The FoxPro 2.6 generator directives for automatically opening and closing the tables are moved to the AutoOpenTables and AutoCloseTables properties in the DataEnvironment object.


FoxPro 2.6 screen feature

Visual FoxPro feature

Screen set

Form set


Form contained in a form set

READ level

Page contained in a page frame

READ screen mode

WindowType property = 2

READ MODAL screen mode

WindowType property = 3


FoxPro 2.6 screen snippet

Visual FoxPro property or event

Form Level

Open Files


Close Files


Window Name


Window Title




















HalfHeight Title Bar












Modifying 2.6 Reports

FoxPro 2.6 reports (.frx files) can be run unmodified from Visual FoxPro 5.0. However, in order to use the Visual FoxPro Report Designer to modify the reports, you will need to convert the FoxPro 2.6 reports to Visual FoxPro reports.

To convert a FoxPro 2.6 report, use the MODIFY REPORT command. The conversion process performs these steps:

  1. Adds a user field to the .frx file.

  2. Changes any Memo fields from 10 bytes to 4 bytes.

  3. Adds records to support the data environment of the report. FoxPro 2.6 environment records convert to data environment records.

  4. Sets the AutoOpenTables and AutoCloseTables properties of the Data Environment and the Destroy event of the new report for backward compatibility with the ENVIRONMENT clause of the FoxPro 2.6 REPORT command.

If the FoxPro 2.6 report was created without an ENVIRONMENT clause, the AutoOpenTables and AutoCloseTables properties of the converted report are set to false (.F.).

If the FoxPro 2.6 report was created with an ENVIRONMENT clause, the AutoOpenTables and AutoCloseTables properties of the converted report are set to true (.T.). The Destroy event of the converted report contains the following code:

THIS.OpenTables && Opens all the tables

THIS.Init && Runs the Init code of the converted report's

                        && DataEnvironment

After converting a report, Visual FoxPro opens the Report Designer so you can add Visual FoxPro functionality to the converted report.

Form Tips

After you convert a FoxPro 2.6 screen (.scx) file, you should check for the following conditions:

Post conversion - extending a Functionally converted form

    You can completely change converted FoxPro 2.6 screens to the Visual FoxPro event model:

To run the form directly, move code from the generated .spr file to appropriate methods in the form so you can run it with the DO FORM command.

Moving a Foundation READ into Visual FoxPro

In FoxPro 2.6, the foundation READ was used to emulate event-driven programming by providing an event loop and handler. In Visual FoxPro, you can take advantage of the native event loop by converting your foundation READs.

Replace any foundation READ in the main program with a READ EVENTS command. For example, include a READ EVENTS command in a .prg program that runs your main form or form set.

Place a CLEAR EVENTS command in the form, menu, or program event that ends the program. For example, assign a CLEAR EVENTS command to the Exit menu item.

You may have code that closes things (tables, windows, etc.) neatly. When you move into the new event model you won't need any of this code, because Visual FoxPro handles it all for you.

Also, check the settings of the form set WindowType property for your converted screens. In FoxPro 2.6, you coordinated screens through READ and READ MODAL statements. These statements are converted to the WindowType property when you convert your files. For backward compatibility, the property is automatically set to 2 or 3, depending on the READ mode of the original screen. To enable full event model functionality once you’ve converted foundation READs, change the READ compatibility mode of screens, remove extra pages and page frames, and change form methods.

More Tips

User Interface

In Visual FoxPro, the TAB key navigates between controls. To move through options in a list box, use the arrow keys.

Some hot keys have changed to conform with the Windows 95 user interface guidelines.

FoxPro 2.6

Visual FoxPro

Definition or difference



Create a new file



Add a record to a Browse window



DO program from within edit window


Variable names

FoxPro 2.6 ignores anything longer than 10 characters, but Visual FoxPro supports and recognizes the longer variable names. If you took advantage of this FoxPro 2.6 "feature", you need to modify your code. To see the difference, run this code in FoxPro 2.6 and then in Visual FoxPro:

store "hello" to clcustomer1
store "goodbye" to clcustomer2

File names

Visual FoxPro also supports longer file names. In FoxPro 2.6 you could have a table called Mynewtab.dbf and this command would work fine: USE MYNEWTABLE. In Visual FoxPro 5.0, this command used on the same file will generate a "file does not exist" error.

There are now 32767 work areas! This affects code that loops through work areas (up to 225). Use AUSED( ) instead. Note that this affects SELECT(1). See what you get by issuing this command in FoxPro 2.6 and Visual FoxPro 5.0.

Table and Database Differences

Visual FoxPro distinguishes between tables and databases. Although FoxPro 2.6 tables are fully functional in Visual FoxPro, if you modify the table structure of FoxPro tables to take advantage of any of the new Visual FoxPro 5.0 table features like acceptance of null values, they are saved as Visual FoxPro tables. Note that if you merely change things like field size, field names, or only add or delete fields the table is maintained as a FoxPro 2.6 file.

FoxPro 2.6 table structure feature or functionality

Visual FoxPro structure feature or functionality

Character field with NOCPTRANS characteristic

Character (BINARY) field type

Date fields

Date data type, DateTime data type

General field size

Now 4 bytes

Memo field size

Now 4 bytes

Memo field with NOCPTRANS characteristic

Memo (BINARY) field type

Numeric fields

Currency data type, Double field type, Float field type, Integer field type, or Numeric data type

OLE data in a General field

OLE Bound control

The structure of Visual FoxPro project (.pjx), screen (.scx), report (.frx), and label (.lbx) files differ from the structure of FoxPro 2.6 files. For details on the structure of Visual FoxPro table files created in the Project Manager, Form Designer, Report Designer, and Label Designer, see Table Structures of Table Files. The filespec directory contains reports you can print out that have specific details of the structures of Visual FoxPro, as well as FoxPro 2.x, tables.

Null Values

Visual FoxPro tables can accept null values. To prevent errors generated by attempts to store null values to FoxPro 2.6 variables or to Visual FoxPro controls, initialize variables or arrays. To prevent users from attempting to store null values to tables, you can disable the NULL entry key combination by using the following statement:


Views in Visual FoxPro

Visual FoxPro allows you to use views as you would tables or queries. If you build a view in Visual FoxPro without qualifying the table name to a database, you’ll get an error when you try to modify the view in the View Designer. To ensure that you can use or modify views in all versions of Visual FoxPro, use CREATE SQL VIEW with the FROM clause as in the following example:

FROM testdata!products	&& testdata is the database name
                && products is the table name

When you specify the source this way, Visual FoxPro searches for the table both in the open database list, including the current and any non-current databases, and in the default search path for the table.

Converting Tables

Visual FoxPro does not change the structure of FoxPro tables unless you add the table to a database, or add a new data type, or enable acceptance of null values. Once you change the structure of a table by adding a new data type such as DateTime, or by enabling null values in a field, Visual FoxPro modifies the table file structure, making the file unrecognizable to FoxPro 2.6.

You can create a FoxPro 2.6 table from a Visual FoxPro table by using the COPY TO command with the TYPE clause and the FOX2X keyword, as in the following example:

* A Visual FoxPro table
USE vfptable.dbf
* Creates a FoxPro 2.6 table
COPY TO fp26tabl.dbf TYPE FOX2X

To copy a FoxPro 2.6 table structure from a Visual FoxPro table, use COPY TO and the NEXT clause, as in the following example.

* Creates an empty FoxPro 2.6 table
COPY TO fp26tabl.dbf NEXT 0 TYPE FOX2X

Visual FoxPro changes all null values in NULL-enabled fields to either 0 or blank, and creates a structure recognized by FoxPro 2.6. Visual FoxPro also converts Integer, Double, and Currency types back to Numeric, and changes DateTime to Date type.

Approach 3 Rewrite

Using this approach, you can keep the data structures and business rules you have already developed. But you will want to take the time to redesign your application to take advantage of OOP structure and functionality. This is the most costly (and time consuming) approach, but it is also the most powerful and flexible. This approach enables you to take advantage of all the new features of Visual FoxPro 5.0. In addition, you will find that you can eliminate hundreds (thousands?) of lines of code because Visual FoxPro 5.0 has built-in functionality that you once had to code yourself.

Many developers claim unequivocally that a rewrite is the way to go, especially with applications that are simple. With the new features of Visual FoxPro 5.0 you will find elegant solutions to problems you needed "kludges" for in FoxPro 2.6. You will begin to develop class libraries to use again and again in future application development.

The best investment of time and resources will be in the design phase of your new application. Learn OOP techniques and learn how they work in Visual FoxPro.

Take advantage of one of Visual FoxPro 5.0's coolest new features to use information from your 2.6 application

Visual FoxPro 5.0's ability to act as a custom ActiveX Automation Server will enable you to use your 2.6 application to provide information to another application.

The Laser sample that ships with FoxPro 2.6 is a laser disk library manager program. The main program is Laser.spr. To turn this into an Automation Server callable from Visual Basic or Microsoft Excel, create a new project in a new main program:

ox = create("laser")
define class laser as custom olepublic
    proc init
        cd d:\fpw26\sample\laser	&& change dir to the right place
        set path to data
        this.application.visible = .t.	&& make us visible.
    proc doit
        do laser.spr

Add the new Laser.spr to the project. You'll need to manually add any supporting files, like .bmp files, to the project. Then, you can try:

OX = Createobject("laser.laser")

and then:


The laser application is now running as an Automation Server! You have effectively wrapped the FoxPro 2.x application, and are using it to "serve" data to other Windows "clients". If you modify the Laser.spr program so that it doesn't close the LASER table when the READ is finished, then you can query what laser disc title was chosen:


Visual FoxPro 5.0 offers many exciting new development opportunities for FoxPro 2.x developers, including better support for client/server, remote and travelling applications; improved debugging; object-oriented designers; and much more. Developers moving from FoxPro 2.x to Visual FoxPro are naturally concerned about migrating their existing applications and skills to the new environment. Visual FoxPro 5.0 offers FoxPro 2.x developers three methods for migrating their FoxPro applications to Visual FoxPro. They range from minimal investment in re-compiling and testing, to modifying, to a full rewrite. The method you choose will be based on your available resources and the users' requirements. With Visual FoxPro 5.0, you can choose the conversion method that best suits your needs.

© 1997 Microsoft Corporation. All rights reserved.