Dropdown list in module pool program

Question

Hi,
I need to display a dropdown list for LFA1-LIFNR in my module pool program.
In the screen painter I have added an Input/Output field with name LFA1-LIFNR and corresponding to the Dropdown option I have selected Listbox. When I execute the program empty dropdown list is coming. It is not taking the values of LIFNR from the table LFA1. Please let me know the solution for this.
Thanks,
Neethu.

Answer 1

Hello Abaper,
You have very well designed the drop-down box that is to be reflected in your program. The next thing for you to do is use any 1 method for populating the values i.e. using the function module F4IF_INT_TABLE_VALUE_REQUEST or VRM values. I prefer to use the the F4IF_INT_TABLE_VALUE_REQUEST as it is easy to use and understand. If you use the following function module then you need to call in a module under the flow logic of the screen i.e. PROCESS ON VALUE REQUEST.
Let me just illustrate you with the syntax -
Module Pool Code
*internal table declaration
TYPES : BEGIN OF ty_lifnr,
                 lifnr TYPE lfa1-lifnr,
END OF ty_lifnr.
DATA : itab_lifnr TYPE STANDARD TABLE OF ty_lifnr.
*Dialog Modules for PBO
*Dialog Module for PAI
MODULE cancel INPUT.
   LEAVE PROGRAM.
*Dialog Module Process on value reuest
MODULE create_dropdownbox INPUT.
   SELECT lifnr
   FROM LFA1
   INTO CORRESPONDING FIELDS OF TABLE itab_lifnr.
CALL FUNCTION 'F4IF_INT_TABLE_VALUE_REQUEST'
   EXPORTING
         retfield      = 'LIFNR'
         value_org = 'S'
   TABLES
         value_tab = itab_lifnr
   EXCEPTIONS
ENDMODULE.
Now for the Flow Logic -
PROCESS BEFORE OUTPUT.
PROCESS AFTER INPUT.
   MODULE cancel AT EXIT-COMMAND.
   MODULE user_command_0100.
PROCESS ON VALUE REQUEST.
   FIELD lfa1-lifnr MODULE create_dropdownbox.
Hope this helps ! Let me know if any other doubts arises.