Get id of selected dropdownlist text

Hello experts,

 

I want to display id of selected text from dropdownlist,

I have below dropdownlist.it shows Name of the dealer but when i select any value from dropdown i want save the id of that value in to database.how can i get the id of selected value.

 

Please help 

 

ViewBag.dealerList = new SelectList(db.tbl_Dealer.ToList(), "Id", "Name");