How to Limit the Number of Characters Typed in a Combo Box

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