OpenEdge Development:<br />Progress 4GL Handbook Populating a list at run time

There are two methods you can use on a selection list, combo box, or radio set to set the value list at run time: ADD-FIRST and ADD-LAST. Each has the same two forms:


`object-handle`:ADD-FIRST(`item-list`) `object-handle`:ADD-LAST(`item-list`) `object-handle`:ADD-FIRST(`label`, `value`) `object-handle`:ADD-LAST(`label`, `value`)

Use ADD-FIRST to add items to the beginning of the list and ADD-LAST to add them to the end. If the object uses the simple List-Items form, in which the actual object values are displayed, then use the item-list form of the method to add one or more items to the list. If the object uses the List-Item-Pairs form, then use the second form of the method to specify a single label followed by the single value it represents.

These types of objects have a DELIMITER attribute to allow you to set a delimiter between items other than the default comma, in case one of the values or labels contains a comma.

The objects also support a logical SORT attribute, which initially is false. If you set SORT to true, then displayed items are sorted by their label. In this case, there is no meaningful difference between using ADD-FIRST and ADD-LAST.

The methods return true if the operation succeeded, and false if for any reason it failed.

Enter this code to complete the initSelection procedure:

/--------------------------------------------------------------------- Purpose: Set the selection list to a list of all the fields in the OrderLine table. Parameters: <none> ---------------------------------------------------------------------/ DEFINE VARIABLE hBuffer AS HANDLE NO-UNDO. DEFINE VARIABLE iFields AS INTEGER NO-UNDO. hBuffer = BUFFER OrderLine:HANDLE. `DO WITH FRAME CustQuery:` `DO iFields = 1 TO hBuffer:NUM-FIELDS:` `OLineFields:ADD-LAST(hBuffer:BUFFER-FIELD(iFields):NAME).` `END.` `END.` END PROCEDURE.

/*--------------------------------------------------------------------- 
  Purpose:     Set the selection list to a list of all the fields in the  
               OrderLine table. 
  Parameters:  <none>     
---------------------------------------------------------------------*/ 
DEFINE VARIABLE hBuffer AS HANDLE     NO-UNDO. 
DEFINE VARIABLE iFields AS INTEGER    NO-UNDO. 
     
    hBuffer = BUFFER OrderLine:HANDLE. 
    DO WITH FRAME CustQuery: 
       DO iFields = 1 TO hBuffer:NUM-FIELDS: 
         OLineFields:ADD-LAST(hBuffer:BUFFER-FIELD(iFields):NAME). 
       END. 
    END. 
END PROCEDURE.

To display these values in the list when the window is viewed, add a RUN statement to the procedure’s main block:

MAIN-BLOCK: DO ON ERROR UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK ON END-KEY UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK: RUN enable_UI. RUN h-StartSuper.p("h-dynsuper.p"). RUN changeFields. `RUN initSelection.` IF NOT THIS-PROCEDURE:PERSISTENT THEN WAIT-FOR CLOSE OF THIS-PROCEDURE. END.

MAIN-BLOCK: 
DO ON ERROR   UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK 
   ON END-KEY UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK: 
  RUN enable_UI. 
  RUN h-StartSuper.p("h-dynsuper.p"). 
  RUN changeFields. 
  RUN initSelection. 
  IF NOT THIS-PROCEDURE:PERSISTENT THEN 
    WAIT-FOR CLOSE OF THIS-PROCEDURE. 
END.