form set_drdn_table.
*¯1.Define a dropdown table and pass it to ALV.
*   One listbox is referenced by a handle, e.g., '1'.
*   For each entry that shall appear in this listbox
*   you have to append a line to the dropdown table
*   with handle '1'.
*   This handle can be assigned to several columns
*   of the output table using the field catalog.
*
  data: lt_dropdown type lvc_t_drop,
        ls_dropdown type lvc_s_drop.

* First listbox (handle '1').
  ls_dropdown-handle = '1'.
  ls_dropdown-value = 'KG'.
  append ls_dropdown to lt_dropdown.

  ls_dropdown-handle = '1'.
  ls_dropdown-value = 'G'.
  append ls_dropdown to lt_dropdown.

  call method g_grid->set_drop_down_table
            exporting it_drop_down = lt_dropdown.

endform.                               " set_drdn_table