Q137183: How to Add Items to a Multiple-Column Combo Box

Article: Q137183
Product(s): Microsoft FoxPro
Version(s): 3.0
Operating System(s): 
Keyword(s): 
Last Modified: 19-FEB-2002

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The information in this article applies to:

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

Combo boxes are designed so that new items can be added to the list or existing
items can be selected from the list. You can do the same thing with
multiple-column combo boxes. This article shows you how.

MORE INFORMATION
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Step-by-Step Procedure
----------------------

1. Create a new form and place a combo box on it.

2. Add the Orders table from the Testdata database to the data environment.

3. Set the following properties for the combo box:

  Property        Value
  -------------------------------------
  Style           0 - Dropdown Combo
  RowSourceType   0 - None
  RowSource       (should be empty)
  ColumnCount     2
  ColumnWidth     50,120
  BoundColumn     1 (this is the default)

  RowSourceType must be set to 0 and RowSource must be empty when items are
  added to the combo box programmatically.

4. Place the following code in the Init event of the combo box:

     SET EXACT ON   && Comparison done in Valid may be comparing blanks
     SELECT orders
     DO WHILE recno()<10   && Fill the combo box with the first 10 records

        ThisForm.Combo1.AddItem(order_id,This.ListCount+1,1)
        ThisForm.Combo1.AddListItem(to_country,This.ListCount,2)
        SKIP

     ENDDO
     This.Value=This.List(1)  && Initialize the value of the combo box

  ListCount is initially 0 because no items are contained in the list. The
  AddItem method places Order_id in column one. ListCount+1 indicates the first
  row added. After the AddItem method is called, ListCount is 1. The
  AddListItem method adds To_country to column two of row one.


5. Place the following code in the Valid event of the combo box to add new
  entries to the list when the form is running:

     in_list=.F.
     IF AT(",",This.DisplayValue)>0
        first=ALLTRIM(LEFT(This.DisplayValue,at(",",This.DisplayValue)-1))
        second=ALLTRIM(RIGHT(This.DisplayValue,LEN(This.DisplayValue);
           -AT(",",This.DisplayValue)))
     ELSE
        first=ALLTRIM(This.DisplayValue)
     ENDIF

     FOR I= 1 to This.ListCount
       IF ALLTRIM(first)=ALLTRIM(This.List(I))
         in_list=.T.
         =MESSAGEBOX("Item number is already in list,"+chr(13)+ ;
            "         item not entered","STOP")
       ENDIF
     ENDFOR

     IF !in_list
       IF AT(",",This.DisplayValue)=0
         =MESSAGEBOX("Comma followed by description needed,"+chr(13)+ ;
            "        item not entered","STOP")
       ELSE
         This.AddItem(first,This.ListCount+1,1)
         This.AddListItem(second,This.ListCount,2)
         This.Value=""
       ENDIF
     ENDIF

  In the For loop, This.DisplayValue contains the current entry in the combo
  box. This.Value has not yet been assigned. If This.DisplayValue is equal to
  some value already in the combo box list, In_list is set to True and the next
  section of code is not run. If it is not found in the list, then the entry in
  the combo box is parsed based on a comma placed between what would be the
  columns one and two. The parsed items are then added to the list by calling
  the AddItem and AddListitem methods. This.List(I) contains only the values in
  column one because the BoundColumn is 1.

6. Run the form. Select items in the list, and add new items to the list by
  entering the Order_id followed by a comma and the to_country.

Additional query words: listbox VFoxWin

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : :3.0

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