How to set value for table lines in web dynpro ?

Question

Hi experts,
I'm new in webdynpro. My requirement is to set value to the second line when user press expand on first line.
In method ONACTIONLOAD_CHILDREN , I use  get_static_attributes_table to get the current table records and change return table value .
Then i user bind_table to pass table to the screen.
It works fine for first time i press expand and collaps, but when i expand it again it throw out a dump 'OBJECTS_OBJREF_NOT_ASSIGNED'.
Could any one please help to solve that?
Thanks

Answer 1

Hi Harsha,
Thanks for your reply,I've check the dump details and it display like this:
Information on where terminated
    Termination occurred in the ABAP program "CL_WDR_CONTEXT_ELEMENT========CP" -
     in "IF_WD_CONTEXT_ELEMENT~SET_ATTRIBUTE".
    The main program was "SAPMHTTP ".
    In the source code you have the termination point in line 40
    of the (Include) program "CL_WDR_CONTEXT_ELEMENT========CM007".
    The termination is caused because exception "CX_SY_REF_IS_INITIAL" occurred in
    procedure "IF_WD_CONTEXT_ELEMENT~SET_ATTRIBUTE" "(METHOD)", but it was neither
     handled locally nor declared
    in the RAISING clause of its signature.
    The procedure is in program "CL_WDR_CONTEXT_ELEMENT========CP "; its source
     code begins in line
    1 of the (Include program "CL_WDR_CONTEXT_ELEMENT========CM007 ".
First time i debug it work fine but the next time it dump with same import values.  And it even did not reach the logic i add when i expand it again.
I'm not sure why it happen.
My code in ONACTIONLOAD_CHILDREN is like this.
*navigate from <CONTEXT> to <ITEM_DATA> via lead selection
  lo_nd_item_data = wd_context->path_get_node( path =
  `COMP_CONTEXT.ITEM_DATA` ).
*get element via lead selection
  lo_el_item_data = lo_nd_item_data->get_element( ).
*get all declared attributes
  lo_nd_item_data->get_static_attributes_table(
    IMPORTING
      table = lt_item_data ).
  LOOP AT lt_item_data INTO ls_item_data.
    IF sy-tabix = 2.
      ls_item_data-description = 'TEST'.
      MODIFY lt_item_data FROM ls_item_data TRANSPORTING description.
    ENDIF.
  ENDLOOP.
    lo_nd_item_data->bind_table( new_items = lt_item_data
    set_initial_elements = abap_true ).
    lo_nd_item_data->set_lead_selection_index( 1 ).
First line was set selected but still got dump.
Could you please help to check this ?
Thanks & Regards
Eric Li