You typically use a DataTemplate to specify the visual representation of your data. DataTemplate objects are particularly useful when you are binding an ItemsControl such as a ListBox to an entire collection. Without specific instructions, a ListBox displays the string representation of the objects in a collection. In that case, you can use a DataTemplate to define the appearance of your data objects. The content of your DataTemplate becomes the visual structure of your data objects.
You can use data binding in a DataTemplate. For example, suppose that a ListBox is bound to a collection of Customer objects and has the ItemTemplate property set to a DataTemplate. When the ListBox is created, a ListBoxItem is created for each Customer in the collection, and the DataContext of the ListBoxItem is set to the appropriate customer. In other words, the DataContext of the first ListBoxItem is set to the first customer, the DataContext of the second ListBoxItem is set to the second customer, and so on. You can bind elements in the DataTemplate to properties of the Customer object.
You can also use a DataTemplate to share UIElement objects across multiple ContentControl objects. For example, suppose you need multiple buttons on your application to have the same graphic. You can create a DataTemplate that contains the graphic and use it as the ContentTemplate for the buttons. For more information, see ContentControl..::.ContentTemplate.
You can place a DataTemplate as the direct child of an object.ItemTemplate property element. You can also define a DataTemplate as a resource and then reference the resource as the value of the ItemTemplate property.
The XAML usage that defines the content for creating a data template is not exposed as a settable property. It is special behavior built into the XAML processing of a DataTemplate object element.