ComboBox

I have a table with following columns: 1)Category_id 2)SubCategory_id (Primary Key) 3)Category_Name I have a textbox displaying category name for subCategory I want to diaplay category_name in combobox corresponding to the category_id and SubCategory_id by by binding all controls so that the user can change that from combo EG. Data CID SubCID Name =============== 1 1 A 1 2 B 1 3 C 2 4 D 3 5 E