Editable ALV - how to throw an error message for a specific line & field

Question

Hi all,
I've implemented an editable ALV and also the ON_DATA_CHECK event to check the values, entered in the ALV. So this works fine and I can check the values.
But now, I want to throw an error message corresponding to the field in the ALV, where the error occured.
How can I throw this error message corresponding to a specific line/field in the ALV?
I was using REPORT_ATTRIBUTE_ERROR_MESSAGE and REPORT_ELEMENT_ERROR_MESSAGE but without success.
I'm also using a loop over the "CHANGES" in the ALV and within this loop, I use
elem_alv = node_alv->get_element( index = <change>-element_index ) 
to get the element for the message.
CALL METHOD lo_message_manager->REPORT_ELEMENT_ERROR_MESSAGE
  EXPORTING
    MESSAGE_TEXT              = 'my message'
    ELEMENT                   = elem_alv
*    ATTRIBUTES                =
*    PARAMS                    =
*    MSG_USER_DATA             =
*    IS_PERMANENT              = ABAP_FALSE
*    SCOPE_PERMANENT_MSG       = CO_MSG_SCOPE_CTXT_ELEMENT
*    MSG_INDEX                 =
*    CANCEL_NAVIGATION         =
*    IS_VALIDATION_INDEPENDENT = ABAP_FALSE.
2.) is it right, that for an editable ALV, I can't use the WDDOBEFOREACTION to do the checks?
If I try to use this, I can't get the values of my ALV table to check it.
Thanks,
Andreas

Answer 1

Hi Andreas,
I have tried to replicate your problem and I am getting the desired output. I have a row by name TEMP_NEW in my ALV and I want to throw an error message whenever the user enters a value of 4 for that particular field. Please find my coding as below. The important thing is where we perform the actual comparison between the r_value and 4. r_value is defined in SALV_WD_S_TABLE_MOD_CELL as reference to type DATA. So suppose the user enters a value of say 3 in the TEMP_NEW field of the ALV then r_value would contain 3 but if you observe its type in debugging mode it would be as TYPE REF TO I and not TYPE I. So you cannot directly say something like:
"if ls_modified_cells-r_value = 3" as this would lead to a syntax error. Define a field-symbol say <temp> and then use it to get the actual value into it by saying like:
ASSIGN ls_modified_cells-r_value->* TO <temp>.
Then you can use this <temp> for comparison in your IF statement like:
IF  <temp> = 3.
Find the entire coding as below:
METHOD check_data.
  DATA: lr_node TYPE REF TO if_wd_context_node,
        lr_element TYPE REF TO if_wd_context_element,
        ls_modified_cells TYPE salv_wd_s_table_mod_cell.
  FIELD-SYMBOLS <temp> TYPE data.
" get message manager
  DATA lo_api_controller     TYPE REF TO if_wd_controller.
  DATA lo_message_manager    TYPE REF TO if_wd_message_manager.
  lo_api_controller ?= wd_this->wd_get_api( ).
  CALL METHOD lo_api_controller->get_message_manager
    RECEIVING
      message_manager = lo_message_manager.
  lr_node = wd_context->get_child_node( name = 'NODE' ).
  LOOP AT r_param->t_modified_cells INTO ls_modified_cells.
    lr_element = lr_node->get_element( index = ls_modified_cells-index ).
    IF ls_modified_cells-attribute = 'TEMP_NEW'.
" Get the value extracted into the field symbol from the reference variable
      ASSIGN ls_modified_cells-r_value->* TO <temp>.
" Use the value present in this field-symbol for your comparison
      IF  <temp> = 4.
" report message
        CALL METHOD lo_message_manager->report_attribute_error_message
          EXPORTING
            message_text   = 'Sample message text'
            element        = lr_element
            attribute_name = ls_modified_cells-attribute.
      ENDIF.
    ENDIF.
  ENDLOOP.
ENDMETHOD.
Hope this helps resolve your problem.
Regards,
Uday