How to: Generate NavBarControl Groups and Items from a Collection

In MVVM scenarios, it's often necessary to generate elements from a collection. NavBarControl provides such a capability via the ItemsSource property. In this example, each object corresponding to NavBarGroup contains a sub-collection of items which will be visualized by NavBarItems. This is sub-collection is bound to the NavBarGroup.ItemsSource property. 

If you wish to group items without specifying NavBarGroup.ItemsSource, use the approach demonstrated at How to: Generate NavBarControl Items from a Collection and Automatically Group Them Depending on a Field Value.