Refresh bei ALV funktioniert nicht

Code: Alles auswählen.

REPORT zz_alv_refresh.

TYPE-POOLS slis.

DATA: it_kna1 TYPE TABLE OF kna1,
      wa_kna1 TYPE kna1,
      it_fieldcat TYPE slis_t_fieldcat_alv.

DATA: gl_repid LIKE sy-repid,
      it_top TYPE slis_t_listheader,
      wa_top TYPE slis_listheader.

FIELD-SYMBOLS <fs_fieldcat> TYPE slis_fieldcat_alv.


START-OF-SELECTION.


* irgendwas für den List-Header
  wa_top-typ = 'A'.
  wa_top-info = 'Info im Listheader'.
  APPEND wa_top TO it_top.


  gl_repid = sy-repid.

* erste 10 Datensätze einlesen
  SELECT * FROM kna1 UP TO 500 ROWS
                     INTO TABLE it_kna1.


* Feldkatalog erstellen
  CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
       EXPORTING
            i_structure_name       = 'KNA1'
       CHANGING
            ct_fieldcat            = it_fieldcat
       EXCEPTIONS
            inconsistent_interface = 1
            program_error          = 2
            OTHERS                 = 3.

* nur KUNNR, NAME1 und NAME2 anzeigen
  LOOP AT it_fieldcat ASSIGNING <fs_fieldcat>
                      WHERE fieldname NE 'KUNNR'
                      AND   fieldname NE 'NAME1'
                      AND   fieldname NE 'NAME2'.
    <fs_fieldcat>-no_out = 'X'.
  ENDLOOP.


* Liste darstellen
  CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
       EXPORTING
            i_callback_program       = gl_repid
            i_callback_pf_status_set = 'SET_PF_STATUS'
            i_callback_user_command  = 'USER_COMMAND'
            i_callback_top_of_page   = 'TOP_OF_PAGE'
            it_fieldcat              = it_fieldcat
       TABLES
            t_outtab                 = it_kna1
       EXCEPTIONS
            program_error            = 1
            OTHERS                   = 2.


* eigenen Status (z.B. aus Kopie von Status Standard
* aus Programm SAPLSALV) setzen mit REFRESH-Button
FORM set_pf_status USING rt_extab TYPE slis_t_extab.
  SET PF-STATUS 'STANDARD' EXCLUDING rt_extab.
ENDFORM.


* Form für den Listkopf
FORM top_of_page.

  CALL FUNCTION 'REUSE_ALV_COMMENTARY_WRITE'
       EXPORTING
            it_list_commentary = it_top.

ENDFORM.


* Klick auf REFRESH behandeln
FORM user_command  USING r_ucomm LIKE sy-ucomm
                         rs_selfield TYPE slis_selfield.

  CASE r_ucomm.

    WHEN 'REFR'.
      LOOP AT it_top INTO wa_top.
        CALL FUNCTION 'STRING_REVERSE'
             EXPORTING
                  string    = wa_top-info
                  lang      = ' '
             IMPORTING
                  rstring   = wa_top-info
             EXCEPTIONS
                  too_small = 1
                  OTHERS    = 2.
        MODIFY it_top FROM wa_top.
      ENDLOOP.
      PERFORM top_of_page.

  ENDCASE.


ENDFORM.