In this topic you will set some of the properties for the C1ComboBoxExtender to change the location of the combobox's arrow, to allow multiple selections, and to allow selections when an item receives focus.

1. Select View | Properties Window in the Visual Studio menu.
2. Click the drop-down list at the top of the Properties window and select C1ComboBoxExtender1.
3. Set the C1ComboBoxExtender.SelectOnItemFocus property to True. In the application, when a user mouses over an item in the drop-down list, it will be selected.
4. Set the C1ComboBoxExtender.TriggerPosition property to Left. This will make the arrow in the combobox appear on the left side of the text box.
5. Set the C1ComboBoxExtender.SelectionMode property to Multiple. This will allow users to select more than one item in the list.

The markup for the C1ComboBoxExtender will now look like this:

<cc1:C1ComboBoxExtender ID="C1ComboBoxExtender1" runat="server"

        TargetControlID="DropDownList1" SelectionMode="Multiple" TriggerPosition="Left" SelectOnItemFocus="True">    </cc1:C1ComboBoxExtender>

Now run the project to see the formatted combobox.