Visual FoxPro


Visual FoxPro is a discontinued Microsoft data-centric procedural programming language that subsequently became object-oriented.
It was derived from FoxPro which was developed by Fox Software beginning in 1984. Fox Technologies merged with Microsoft in 1992, after which the software acquired further features and the prefix "Visual". FoxPro 2.6 worked on Mac OS, DOS, Windows, and Unix.
Visual FoxPro 3.0, the first "Visual" version, reduced platform support to only Mac and Windows, and later versions 5, 6, 7, 8 and 9 were Windows-only. The current version of Visual FoxPro is COM-based and Microsoft has stated that they do not intend to create a Microsoft.NET version.
Version 9.0, released in December 2004 and updated in October 2007 with the SP2 patch, was the final version of the product.

History

Visual FoxPro originated as a member of the class of languages commonly referred to as "xBase" languages, which have syntax based on the dBase programming language. Other members of the xBase language family include Clipper and Recital.
Visual FoxPro, commonly abbreviated as VFP, is tightly integrated with its own relational database engine, which extends FoxPro's xBase capabilities to support SQL query and data manipulation. Unlike most database management systems, Visual FoxPro is a full-featured, dynamic programming language that does not require the use of an additional general-purpose programming environment. It can be used to write not just traditional "fat client" applications, but also middleware and web applications.
In late 2002, it was demonstrated that Visual FoxPro can run on Linux under the Wine Windows compatibility suite. In 2003, this led to complaints by Microsoft: it was claimed that the deployment of runtime FoxPro code on non-Windows machines violates the End User License Agreement.
Visual FoxPro had a rapid rise and fall in popularity as measured by the TIOBE Programming Community Index. In December 2005, VFP broke into the top 20 for the first time. In June 2006 it peaked at position 12, making it a "B" language. As of October 2019, Visual FoxPro holds position 51 on the TIOBE index.
In March 2007, Microsoft announced that there will be no VFP 10, thus making VFP9 the last commercial VFP release from Microsoft. Service Pack 2 for Microsoft Visual FoxPro 9.0 was released on October 16, 2007. The support of Version 9 ended on January 13, 2015.
At the time of the end of life announcement, work on the next release codenamed Sedna which was built on top of the VFP9 codebase had already begun. "Sedna" is a set of add-ons to VFP 9.0 of xBase components to support a number of interoperability scenarios with various Microsoft technologies including SQL Server 2005,.NET Framework, Windows Vista, Office 2007, Windows Search and Team Foundation Server. Microsoft released Sedna under the Shared source license on the CodePlex site. Microsoft has clarified that the VFP core will still remain closed source. Sedna was released on January 25, 2008. As of March 2008, all xBase components of the VFP 9 SP2 were available for community-development on CodePlex.
In late March 2007 a grassroots campaign was started by the Spanish-speaking FoxPro community at MásFoxPro to sign a petition to Microsoft to continue updating Visual FoxPro or release it to the community as open-source. On April 3, 2007 the movement was noted by the technical press.
On April 3, 2007, Microsoft responded to the petition with this statement from Alan Griver:

"We're very aware of the FoxPro community and that played a large part in what we announced on March 13th. It's never an easy decision to announce that we're not going to release another version of a product and it's one that we consider very carefully.
"We're not announcing the end of FoxPro: Obviously, FoxPro applications will continue to work. By some of our internal estimates, there are more applications running in FoxPro 2.6 than there are in VFP and FoxPro 2.6 hasn't been supported in many years. Visual FoxPro 9 will be supported by Microsoft through 2015.
"For Microsoft to continue to evolve the FoxPro base, we would need to look at creating a 64-bit development environment and that would involve an almost complete rewrite of the core product. We've also invested in creating a scalable database with SQL Server, including the freely available SQL Server Express Edition. As far as forming a partnership with a third-party is concerned, we've heard from a number of large FoxPro customers that this would make it impossible for them to continue to use FoxPro since it would no longer be from an approved vendor. We felt that putting the environment into open source on CodePlex, which balances the needs of both the community and the large customers, was the best path forward."

Version Timeline

All versions listed are for Windows.
VersionRelease Date
Visual FoxPro 3.0June 1995
Visual FoxPro 5.0October 1996
Visual FoxPro 5.0aOctober 1997
Visual FoxPro 6.018 May 1998
Visual FoxPro 7.027 June 2001
Visual FoxPro 8.01 February 2003
Visual FoxPro 8.0 Service Pack 17 October 2003
Visual FoxPro 920 December 2004
Visual FoxPro 9 Service Pack 18 December 2005
Visual FoxPro 9 Service Pack 216 October 2007

Code samples

The FoxPro language contains commands quite similar to other programming languages such as Basic.
Some basic syntax samples:

FOR i = 1 to 10
x = x + 6.5
NEXT && Instead of "NEXT" can also use "ENDFOR"
IF i = 25
i = i + 1
ELSE
i = i + 3
ENDIF
x = 1
DO WHILE x < 50
x = x + 1
ENDDO
x = 1
DO WHILE.T.
x = x + 1
IF x < 50
LOOP
ELSE
EXIT
ENDIF
ENDDO
nMonth = MONTH)
DO CASE
CASE nMonth <= 3
MESSAGEBOX
CASE nMonth <= 6
MESSAGEBOX
CASE nMonth <= 9
MESSAGEBOX
OTHERWISE
MESSAGEBOX
ENDCASE
FOR EACH oControl IN THISFORM.Controls
MESSAGEBOX
ENDFOR
f = Factorial
FUNCTION Factorial
LOCAL i, r
r = 1
FOR i = n TO 1 STEP -1
r = r * i
NEXT && Can also use "ENDFOR" here instead of "NEXT"
RETURN r
ENDFUNC

Hello World examples:

* Output at the current location
? "Hello World"
* Output at a specified location
@ 1,1 SAY "Hello World"
* Output in a separate window, cleared on input
WAIT WINDOW "Hello World"
* Output in a standard dialog box, cleared on OK
MESSAGEBOX

Object


  • Output in a defined window
loForm = CREATEOBJECT
loForm.Show
DEFINE CLASS HiForm AS Form
AutoCenter =.T.
Caption = "Hello, World"
ADD OBJECT lblHi as Label ;
WITH Caption = "Hello, World!"
ENDDEFINE


loMine = CREATEOBJECT
? loMine.cProp1 && This will work.
? loMine.cProp2 && Program Error: Property CPROP2 is not found because it's hidden externally.
? loMine.MyMethod1 && This will work.
? loMine.MyMethod2 && Program Error: Property MYMETHOD2 is not found because it's hidden externally.
DEFINE CLASS MyClass AS Custom
cProp1 = "My Property" && This is a public property
HIDDEN cProp2 && This is a private property
dProp3 = && Another public property
PROCEDURE Init && Class constructor
This.cProp2 = "This is a hidden property."
PROCEDURE dProp3_Access && Property Getter
RETURN DATE
PROCEDURE dProp3_Assign && Property Setter uses the "_assign" tag on the property name
IF VARTYPE = "D"
THIS.dProp3 = vNewVal
ENDIF
PROCEDURE MyMethod1
* This is a public method, calling a hidden method that returns
* the value of a hidden property.
RETURN This.MyMethod2
HIDDEN PROCEDURE MyMethod2 && This is a private method
RETURN This.cProp2
ENDDEFINE

The language also has extensive database manipulation and indexing commands.
The "help" index of commands in VFP 9 has several hundred commands and functions described.
The examples below show how to code the creation and indexing of tables, however VFP has table and database builder screens which create the tables and indexes without making you write code.

* Create a table
CREATE TABLE randData
* Populate with random data using xBase and SQL DML commands
FOR i = 1 TO 50
APPEND BLANK
REPLACE iData WITH
INSERT INTO randData VALUES
ENDFOR
* Place a structural index on the data
INDEX ON iData TAG iData
CLOSE DATA && Do not close open libraries etc
* Display ordered data using xBase-style commands
USE randData
SET ORDER TO iData
LOCATE && In place of GO TOP. Enforces use of index to find TOP
LIST NEXT 10 && First 10
GO BOTTOM
SKIP -10
LIST REST && Last 10
CLOSE DATA
* Browse ordered data using SQL DML commands
SELECT * ;
FROM randData ;
ORDER BY iData DESCENDING

ODBC access using SQL passthrough


PRIVATE cAuthorID, cAuthorName && Private variables supplant any previous global or private variable of the same name
LOCAL nHnd, nResult && Local variables are visible only here
* Connect to an ODBC data source
nHnd = SQLCONNECT
* Enter a loop so we can exit to the close connection code if there's an error
DO WHILE.T.
* Execute a SQL command
nResult = SQLEXEC
IF nResult < 0
MESSAGEBOX
EXIT && To close the connection
ENDIF
* Retrieve data from the remote server and stores it in a local data cursor
nResult = SQLEXEC
IF nResult < 0
MESSAGEBOX
EXIT && To close the connection
ENDIF
* Update a record in a remote table using parameters
cAuthorID = "1001"
cAuthorName = "New name"
nResult = SQLEXEC
IF nResult < 0
MESSAGEBOX
EXIT && To close the connection
ENDIF
* If we get here, we have retrieved everything successfully
EXIT && Exit unconditionally
ENDDO
* Close the connection
SQLDISCONNECT

Applications

Some notable applications written in Visual FoxPro include