CL_GUI_ALV_TREE Event CHECKBOX_CHANGE

Question

Dear Experts,
i use a tree control using class cl_gui_alv_tree.
All fields of my fieldcatalog are specified as fieldcat-checkbox = 'X' and fieldcat-edit = 'X'.
i have a global class zcl...... where i implemeted a method as event_handler for class cl_gui_alv_tree for event checkbox_change.
i set the event handler before i set_table_for_first_display.
Set event handler for clicks on hotspots
  SET HANDLER go_qual_block->hndl_checkbox_change FOR p_go_alv_tree.
  ls_header-tooltip   =
  ls_header-heading   = 'Blocking Materials'(008).
  ls_header-width     = 50.
  ls_header-width_pix = abap_false.
  CALL METHOD p_go_alv_tree->set_table_for_first_display
    EXPORTING
     I_STRUCTURE_NAME     =
     IS_VARIANT           =
     I_SAVE               =
      i_default            = abap_false
      is_hierarchy_header  = ls_header
     IS_EXCEPTION_FIELD   =
     IT_SPECIAL_GROUPS    =
     IT_LIST_COMMENTARY   =
     I_LOGO               =
     I_BACKGROUND_ID      =
     IT_TOOLBAR_EXCLUDING =
    CHANGING
      it_outtab            = <go_data_tab>
     IT_FILTER            =
      it_fieldcatalog      = lt_fcat.
.... add nodes.... frontend_update....
But when i start the program an click on a checkbox nothing happens. Is the event not triggered?
I searched for examples which handels the event checkbox_change but i don't find anything.
Is there a special handling for this event?
thanks in advance.
best regards,
Dennis

Answer 1

Hello thanks for this answer it was helpful but i have not solved the problem.
My fault was, that i havn't registered the event before setting the event handler.
but now i have a new problem to register the event.
  l_event-eventid = cl_gui_column_tree=>eventid_checkbox_change.
  APPEND l_event TO lt_events.
  CALL METHOD p_go_alv_tree->set_registered_events
    EXPORTING
      events                    = lt_events
    EXCEPTIONS
      cntl_error                = 1
      cntl_system_error         = 2
      illegal_event_combination = 3.
  IF sy-subrc <> 0.
    MESSAGE x208(00) WITH 'ERROR'.                          "#EC NOTEXT
  ENDIF.
Set event handler for clicks on hotspots
  SET HANDLER go_qual_block->hndl_checkbox_change FOR p_go_alv_tree.
it comes back with sy-subrc = 3.
triggered because item_selection inside the registration.
But i don't know where this item_selection has to be set.
LOOP AT EVENTS INTO SIMPLE_EVENT.
    CASE SIMPLE_EVENT-eventid.
      " base events
      when eventid_node_keypress.
      WHEN EVENTID_EXPAND_NO_CHILDREN.
      WHEN EVENTID_NODE_DOUBLE_CLICK.
        IF NOT SEL_CHANGE_USED IS INITIAL.
          RAISE ILLEGAL_EVENT_COMBINATION.
        ENDIF.
      WHEN EVENTID_SELECTION_CHANGED.
      WHEN EVENTID_NODE_CONTEXT_MENU_REQ
           or EVENTID_DEF_CONTEXT_MENU_REQ.
        " register context menu select event
        REG_CTX_MEN_SELECT = 'X'.
      " header
      when EVENTID_HEADER_CONTEXT_MEN_REQ.
        " register context menu select event
        REG_CTX_MEN_SELECT = 'X'.
      WHEN EVENTID_HEADER_CLICK.
        HEADER_CLICK_USED = 'X'.
      " item events
      WHEN EVENTID_BUTTON_CLICK
        OR EVENTID_LINK_CLICK
        OR EVENTID_CHECKBOX_CHANGE
        OR EVENTID_ITEM_DOUBLE_CLICK
        or eventid_item_keypress.
          IF ITEM_SELECTION IS INITIAL.
                                                                                RAISE ILLEGAL_EVENT_COMBINATION.
          ENDIF.
      WHEN EVENTID_ITEM_CONTEXT_MENU_REQ.
        IF ITEM_SELECTION IS INITIAL.
          RAISE ILLEGAL_EVENT_COMBINATION.
        ENDIF.
        " register  context menu select event
        REG_CTX_MEN_SELECT = 'X'.
      WHEN OTHERS.
        RAISE ILLEGAL_EVENT_COMBINATION.
    ENDCASE.
Best regards,
Dennis