How to: Add DropDownList Web Server Controls to a Web Forms Page (Visual Studio)
The process of adding aWeb server control to a page consists primarily of setting options that specify how items should be displayed and whether users can select multiple items.
To add a DropDownList Web server control to a Web Forms page
From the Standard tab of the Toolbox, drag a DropDownList control onto the page.
Adding items to the control is a separate process that depends on whether you will display a static list in the control or a list that is generated dynamically at run time. For details, see.