Creating and implementing the NavigationService interface

In this section, we will take a look at how to create the INavigationService class, which will essentially contain various instance methods that will be used by our BaseViewModel class, that each of our ViewModels class constructors will implement in the INavigationService interface. The advantage of creating an INavigationService class is that it's much easier to add additional class instance methods that will be used by those ViewModels that utilize this interface.

Let's start by creating the NavigationService class for our TrackMyWalks app by performing the following steps:

1. Ensure that the TrackMyWalks solution is open within the Visual Studio for Mac IDE.

2. Next, right-click on the TrackMyWalks project, and choose Add|New Folder from the pop-up menu, as shown in the following screenshot:

Creating the Services...