DOCUMENT:Q136010  15-FEB-2000  [foxpro]
TITLE   :How to Use a Custom Method as a User-Defined Function (UDF)
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:3.0
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, version 3.0 
-------------------------------------------------------------------------------

SUMMARY
=======

This article gives details about how to create and use custom methods.

In FoxPro version 2.x, you can define procedures and functions in the cleanup
code of FoxPro version 2.x screens. Forms in Visual FoxPro don't have an
analogous place for defining procedures and functions, so you can:

 - Put cleanup code in a procedure file contained in the Project Manager, and
   issue a SET PROCEDURE TO statement.

-or-

 - Create functions and procedures as custom methods of the form. These custom
   methods can then be referenced the same as any other method of the form or
   other object.

MORE INFORMATION
================

Custom methods can be coded to behave as functions behave; that is, they can
return a value simply by ending the code definition with RETURN x where x is the
name of a variable whose value is set in the method.

Custom methods should not begin with the PROCEDURE or FUNCTION command, which is
normally used to indicate that a procedure or function is being defined, nor
should they end with ENDPROC or ENDFUNC.

Step-by-Step Example
--------------------

1. Create a new form, and add two text boxes (Text1 and Text2) and two command
   buttons (Command1 and Command2).

2. Add the Customer and Orders tables from the Testdata database to the data
   environment of the form.

3. Set the ControlSource for the Text1 box to:

      customer.cust_id

4. Set the ReadOnly property for the Text1 box to True (.T.).

5. Leave the ControlSource property for the Text2 box blank.

6. On the Form menu, click New Method. Enter Custcount as the name of the new
   method.

7. Change the caption of the Command1 button to "Count orders," and enter the
   following code in the Click event procedure:

      nNum = thisform.custcount()
      thisform.text2.value = nNum
      thisform.refresh

8. Change the caption of the Command2 button to Skip, and enter the following
   code in the Click event procedure:

      skip
      thisform.refresh

9. Enter the following code for the Custcount custom method:

      x = 0
      select orders
      go top
      count to x for orders.cust_id = thisform.text1.value
      select customer
      return x

When you click the Count orders button, the Custcount custom method is called to
count how many orders exist in the Orders table for the current record in the
Customer table. This number is returned to the Count orders button.

Additional query words: VFoxWin

======================================================================
Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : WINDOWS:3.0

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2000.