You use drop-down lists to create a single-selection drop-down list control. (You can't select multiple items in this control because when you make a selection from the list, the list closes automatically.) You can see a drop-down list at work in Figure 17.4; this is the DropDownLists example on the CD-ROM—where I'm making a selection.
After you've selected an item in a drop-down list, you can use the control's SelectedItem and SelectedIndex properties to work with the selection. The DropDownLists example displays the selection you've made, as you see in Figure 17.5.
As with Web server list boxes, drop-down lists are supported with <select> controls; here, the <select> controls are drawn to display only one item in the list at a time. Here's the HTML that creates the drop-down list you see in Figure 17.5: