display itemName in cbobox according to itemtype selected

Question

I want to display ItemName according to selected  ItemType stored in sql database.

example 

t

• Fruits

1. Apple
2. Mango
3. Orange

• Vegetable

1. Onion
2. Ginger
3. Radish

• Drinks

1. Vodka
2. Pepsi
3. Coco-cola

here ItemType are in bullet which contain ItemName are in number formate and I want to display the ItemName in combo-box according to selected ItemType from combo-box.Llike if user click Fruits  in cboItemType then apple,mango,orange should be loaded cboItemType from database. Please help. . .