DropDownList Server Control
The DropDownList server control allows you to place an HTML select box on your web page when you have a large collection of items from which you want to select a single item.
The select box generated by the DropDownList control displays a single item and allows you to make a selection from a larger list of items. Depending on the number of choices available in the select box, you may have to scroll through a list of items. The appearance of the scroll bar in the drop-down list is automatically created by the browser depending on the number of items contained in the list.