Question

I want to make list which will display values, like text item but in list.

My code:

DECLARE
      rg_dept     RecordGroup;
   
      rg_dname    VARCHAR2(4) := 'Name';
     
      dlist_ID    Item := Find_Item('PROJESCT.LIST_ID');
    
      nDummy      NUMBER;
BEGIN
      rg_dept := Find_Group(rg_dname);
   
     
      -- Delete any existing Group first
      IF NOT Id_Null(rg_dept) THEN
            Delete_Group(rg_dept);
      END IF;
  
      -- Now create a Record Group using a SQL query
      -- Your Query must have a Label and a Value (two Columns)
      -- and the data types must match your item type   
      rg_dept := Create_Group_From_Query(rg_dname,'SELECT department_name, to_char(department_id) FROM departments');
    
 
      --Clear the existing List
      Clear_List(dlist_ID);
   
 
      -- Populate the Record Group
      nDummy := Populate_Group(rg_dept);
      
 
      -- Populate the List Item
      Populate_List(dlist_ID ,rg_dept);
     
END;

If I make list item and add this code, form will display nothing; if I remove list, all is ok.

P.S. Trigger: when-list-item-change

Answer 1

I should recommend you to populate your lists from e.g. When-new-Form-Instance. As usual you will get a good idea what you need to do from Forms help (menu ‘Help/Online Help’). This is a procedure I have made to simple populate list only by specifying the name of the list item and the select statement to populate the lsit item with.

PROCEDURE populate_list_item (
  p_item_name   VARCHAR2
, p_select  VARCHAR2
) IS
    l_rg_id         RECORDGROUP;
    l_list_id       ITEM;
    l_err_num       PLS_INTEGER;

    FUNCTION create_temp_group (
      p_select      VARCHAR2
    ) RETURN RECORDGROUP IS
        l_rg_id     RECORDGROUP;
        l_group_name    VARCHAR2(30) := 'TMP$RG';
    BEGIN
        l_rg_id := FIND_GROUP(l_group_name);

        --Make sure that record group don't alreay exist
        IF NOT ID_NULL(l_rg_id) THEN
           DELETE_GROUP(l_rg_id);
        END IF;

        --Populate the temporary record group
        l_rg_id := CREATE_GROUP_FROM_QUERY(l_group_name, p_select);

        RETURN l_rg_id;
    END create_temp_group;

BEGIN
    l_rg_id := create_temp_group(p_select);

    l_err_num := Populate_Group(l_rg_id);

    --Allow for no data found in the selection query
    IF l_err_num NOT IN (0, 1403) THEN
        RAISE Form_Trigger_Failure; 
    END IF;

    l_list_id := Find_Item(p_item_name);
    IF ID_NULL(l_list_id) THEN
        RAISE Form_Trigger_Failure; 
    END IF;

    Populate_List(l_list_id, l_rg_id);

    Delete_Group(l_rg_id);
END populate_list_item;

The When-New-Form-Instance is a form level trigger and should be under the form (instead of block or item):