HI Kalpana,
You can use the class "cl_crm_ml_category_util" like below:
CALL METHOD cl_crm_ml_category_util=>get_categoryfirst
EXPORTING
iv_ref_guid = me->guid "guid of transaction
iv_ref_kind = 'A'
IMPORTING
er_category = o_category.
o_category->get_details( IMPORTING
ev_cat = wa_cat ).
CREATE OBJECT o_cat
EXPORTING
iv_asp_guid = wa_cat-cat-asp_guid.
o_cat->get_ddlb_coupled_new( EXPORTING
iv_cat_guid = wa_cat-cat_guid
IMPORTING
et_ddlb_config = it_ddlb_config ).
In the end you can use the internal table it_ddlb_config to do what you want.
Regards,
Anderson Balieiro