GRID EDIT IN 2 TIER

1)    ITEMCODE,ITEMNAME.OUANTITY,RATE,AMOUNT  ARE THE COLUMNS SHOULD  FILLED IN GRIDVIEW,WHEN I CLICK ROWHEADER ,TO EDIT PURPOSE.CAN I HAVE SIMPLE CODE?
2)WHEN I PREE F5 IN THE PLACE OF ITEMCODE,ITEMS SHOULD LISTED IN LISTBOX INSIDE THE GRID...HOW TO WRITE CODE IN F5?