Use the DropDownList control to create a single-selection drop-down list control. You can control the appearance of the DropDownList control by setting the BorderColor, BorderStyle, and BorderWidth properties.
To specify the items that you want to appear in the DropDownList control, place a ListItem object for each entry between the opening and closing tags of the DropDownList control.
The DropDownList control also supports data binding. To bind the control to a data source, create a data source, such as a System.Collections.ArrayList object, that contains the items to display in the control. Then, use the Control.DataBind method to bind the data source to the DropDownList control.
Use the SelectedIndex property to programmatically determine the index of the item selected by the user from the DropDownList control. The index can then be used to retrieve the selected item from the Items collection of the control.
ASP.NET Video Tutorial Dropdownlist control Video Tutorial By Kudvenkat what is dropdownlist control