NavigationService.BackStack.FirstOrDefault() does not contains definition in Windows Phone 8?

Question

I am trying to get the last page in the navigation using the following in WP8

var lastPage = NavigationService.BackStack.FirstOrDefault();

However Visual Studio 12 complaints that it does not contain a definition for FirstOrDefault

Answer 1

Don't forget to add using System.Linq; at the top of your code file.