im trying to create a simple billing software to generate a bill i need help

hi all,

i m new to wpf windows application well i hav created insert, update, and delete of item code, name and price.

n i hav bind the item code to the combo box too,

n now i want to create a bill in which if i select a item code in combo box then consequent item name should be displayed and individual price of item should be multiplied with the quantity entered in textbox and displayed in labels or textbox etc.

how can i do dat pls help

thanks & regards