There are a lot of scenarios where you might want to share contextual information between the view that is hosting a region and a view that is inside a region. For example, a master detail–like view shows a business entity and exposes a region to show additional detail information for that business entity. The Prism Library uses a concept named RegionContext to share an object between the host of the region and any views that are loaded inside the region, as shown in the following illustration.
大意就是,在父視圖中,添加一個Region,用來顯示擴充資訊,并且指定這個Region的DataContext(但是官方說This approach is somewhat similar to the DataContext, but it does not rely on it.),也就是說,僅僅是像而已!也就是說,不不用再為這個即将加載進來的視圖,單獨設定DataContext,任何一個加載進來的視圖都共享這個RegionContext。