Binding an ArrayList to dropdownlist

I have got a

txtCarName, txtCarPrice, ddlCarModel

and two arraylist

 ArrayList CarModel

ArrayList CarPrice 

say for example I enter the car name in the textbox, then I need them to bind ArrayList CarModel to ddlCarModel and depending on the selected value in the dropdownlist I should display that value in the txtCarPrice from the ArrayList CarPrice.

 Any Ideas 

Thanks
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