Hi Venkat,
We can achieve the HIERARCHY through the following code.In this case I have used CARRID as the drill down column.
data lo_cmp_usage type ref to if_wd_component_usage.
lo_cmp_usage = wd_this->wd_cpuse_flight_tree( ).
if lo_cmp_usage->has_active_component( ) is initial.
lo_cmp_usage->create_component( ).
endif.
DATA lo_INTERFACECONTROLLER TYPE REF TO IWCI_SALV_WD_TABLE .
lo_INTERFACECONTROLLER = wd_this->wd_cpifc_flight_tree( ).
DATA lv_value TYPE ref to cl_salv_wd_config_table.
lv_value = lo_interfacecontroller->get_model(
).
lv_value->IF_SALV_WD_TABLE_SETTINGS~SET_DISPLAY_TYPE( IF_SALV_WD_C_TABLE_SETTINGS=>DISPLAY_TYPE_HIERARCHY ).
"Enable HIERARCHY structure
data lr_col type ref to CL_SALV_WD_COLUMN.
lr_col = lv_value->IF_SALV_WD_COLUMN_SETTINGS~GET_COLUMN( 'CARRID' )." Enable HIERARCHY for the col. specified
lr_col->IF_SALV_WD_COLUMN_HIERARCHY~SET_HIERARCHY_COLUMN( ABAP_TRUE ).
Regards,
Harsha