Editable alv: add custom validation and display "errors" in protocol list

Question

Hi,
What I want to do:
PAI validation of editable alv with displaying error's in the protocol list by adding custom entries to the existing protocol object.
What is my problem:
After registering "data_changed event", the protocol list don't appear.
My understanding is, that the object "er_data_changed" is passed by the event "data_changed"
an so I thought I can add some more entries to the protocol list.
After "de-registering" the "data_changed" event, the protocol appears with the standard errros messages (e.g. "input to numeric" by enter charachters)
One more hint:
By creating a new object "er_data_changed" in the handler method the protocol list works, but I would like to append entries to the object that was passed with the event.
Probably I've misunderstand something, please help !
My coding:
PAI:
trigger event "data_changed" -> calls handler method
  CALL METHOD r_myalv->check_changed_data
    IMPORTING
      e_valid = is_valid.
stop processing
  IF is_valid NE 'X'.
    MESSAGE 'invalid input' TYPE 'E' .
  ENDIF.
handler method:
handle_data_changed FOR EVENT data_changed  OF cl_gui_alv_grid  IMPORTING e_ucomm
                                                                                er_data_changed.
METHOD handle_data_changed.
    data: ls_mod_cell type lvc_s_modi.
     CALL METHOD er_data_changed->add_protocol_entry
                EXPORTING
                       i_msgid     = 'SU'
                       i_msgty     = 'E'
                       i_msgno     = '000'
                       i_msgv1     = 'This is a test !'
                       i_fieldname = ls_mod_cell-fieldname.
     er_data_changed->refresh_protocol( ).
     er_data_changed->DISPLAY_PROTOCOL( ).
ENDMETHOD.                    "handle_data_changed

Answer 1

Dear Olaf,
    If understood correctly, you want to Edit an ALV and do some data validations when some data is changed in an ALV.   To do this follow the following steps:
1.   Before displaying ALV, Register the edit event.
* Set cell modified to trigger data_changed
CALL METHOD go_alv_grid->register_edit_event
EXPORTING
i_event_id = cl_gui_alv_grid=>mc_evt_modified.
2.  Register the event DATA_CHANGED of class CL_GUI_ALV_GRID & handle the event.
SET HANDLER lo_event_receiver->handle_data_changed FOR go_alv_grid.
The event DATA_CHANGED of class CL_GUI_ALV_GRID has a parameter ER_DATA_CHANGED which is of type CL_ALV_CHANGED_DATA_PROTOCOL.
This er_data_changed has internal table MT_MOD_CELLS(contains index of records changed ) & MP_MOD_ROWS(contains the changed row), using these update your internal table accordingly.
DATA : wa_mod_cell TYPE lvc_s_modi.
FIELD-SYMBOLS: <fs> TYPE table.
LOOP AT er_data_changed->mt_mod_cells INTO wa_mod_cell.
ASSIGN er_data_changed->mp_mod_rows->* TO <fs>.
READ TABLE <fs> INTO wa_output INDEX wa_mod_cell-tabix.
MODIFY lt_output FROM wa_output INDEX wa_mod_cell-row_id.
ENDLOOP.
3.   Here it self you can do the required data validations(No need of any PAI modules) as below.
IF wa_orders-zfstfirmtyp = c_9.
MESSAGE s288(zcsp).
DELETE er_data_changed->mt_mod_cells.
EXIT.
ENDIF.
Regards
Kesava