DOCUMENT:Q138499  11-FEB-2000  [foxpro]
TITLE   :How to Limit the Number of Characters Typed in a Combo Box
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
=======

You can limit the number of characters that a user can type into a text box by
using the InputMask property. However, this property does not exist for a combo
box. This article shows shows by example how to limit the number of characters
typed in a combo box by placing code in the KeyPress event.

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

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

1. Create a new form.

2. On the Form menu, click New Property, and name the new property numb.

3. Place a combo box on the form, and set its ControlSource, RowSourceType, and
   RowSource properties.

4. Place at least one other control on the form.

5. Place the following code in the KeyPress event for the combo box to limit the
   number of characters entered into the combo box to 3:

     IF nKeyCode=13 OR nKeyCode=9   && test for ENTER or TAB
        THISFORM.numb=0              && and reset numb
      ELSE
        IF !(nkeyCode=127 OR ;       &&  BACKSPACE
          nkeyCode=7 OR ;            &&  DELETE
          nkeyCode=6 OR ;            &&  END key
          nkeyCode=19 OR ;           &&  LEFT ARROW
          nkeyCode=4 OR ;            &&  RIGHT ARROW
          nkeyCode=1)                &&  HOME key
          THISFORM.numb=THISFORM.numb+1  && if not one of the above increment

            IF THISFORM.numb=4       && When 4 characters have been entered
              THISFORM.numb=0        && reset numb to zero and flash a message
              ?? CHR(7)              && ring the bell
              =MESSAGEBOX("Enter only 3 characters")
              NODEFAULT              &&  do not enter the character typed.
            ENDIF
        ENDIF
      ENDIF

Additional query words: VFoxWin mask format

======================================================================
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.