There are several ways to populate DropDownList control. In this article autor have tried to cover some of them including populating DropDownList manually, programmatically, through xml, database, arraylist, hashtable. Author have also covered how to specify different background color of every items of the DropDownList and how to generate DropDownList on the fly. At last he have covered how to get its index, text and value properties.

http://www.dotnetfunda.com/articles/article30.aspx