ComboBox
The ComboBox control provides a drop-down version of the ListBox control, allowing for the selection from multiple, contiguous or non-contiguous items in a list. Since a ComboBox takes up less space than a fully exposed list of items, the use of a ComboBox is often preferred.
Properties
The ComboBox control has Items and ItemsSource properties. During design-time, the user can configure the Items property with items to be used as the ComboBox drop-down list. The user can also specify a binding to the ItemsSource property via the Set Data Binding function.
During run-time, the ItemsSource property, if set, will take precedence over the Items property. In other words, if both the Items and the ItemsSource properties are set, ItemsSource will be used instead of the Items property.