PRB: The REQUIRED Clause of VALID Is Not Supported in FoxPro

• Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b, 2.6
• Microsoft FoxPro for MS-DOS, versions 2.0, 2.5, 2.5a, 2.5b, 2.6
• Microsoft FoxPro for Macintosh, version 2.5b

SYMPTOMS

The VALID clause of a GET is executed when no changes have been made to the field or memory variable.

CAUSE

In dBASE IV, the VALID clause of a GET is executed only when the contents of the GET field or memory variable have been changed. The VALID clause is not executed when the cursor is moved out of a GET field or memory variable and no changes were made to the contents of that field or memory variable. In FoxPro, the VALID clause of a GET is always executed when the cursor is moved out of the GET. dBASE IV provides a REQUIRED clause for the VALID clause.

In dBASE, this optional clause is used to force a VALID to be executed when the cursor is moved out of a field or memory variable even if no changes were made to the field or memory variable. The REQUIRED clause is ignored in FoxPro.

RESOLUTION

This is a known incompatibility for which a workaround has not been established.

MORE INFORMATION

Steps to Reproduce Problem

Execute the following code in dBASE IV and FoxPro:

   test1 = SPACE(10)
   test2 = SPACE(10)

   @ 10,10 GET test1 VALID myfunc()
   @ 11,10 GET test2

   READ

   FUNCTION myfunc
        ? "In Valid"
   RETURN .T.