Understanding the IMvxNavigationService

IMvxNavigationService is an abstraction for the native navigation. Actually, it uses ViewModel to navigate, not from View to View. That means that we do not need to use platform-specific navigation, and MvvmCross will find the correct View to show.

IMvxNavigationService supports a lot of different async methods to implement navigation. You can find all the interfaces here: https://github.com/MvvmCross/MvvmCross/blob/develop/MvvmCross/Navigation/IMvxNavigationService.cs. Get started from a simple one:

Task Navigate<TViewModel>(IMvxBundle presentationBundle = null) where TViewModel : IMvxViewModel;

By this method, we can navigate to a new ViewModel without specifying the View we want to navigate to. MvvmCross will find the right view which is associated with this ViewModel.

If we need to pass a param to the new ViewModel, there is another method to do this:

Task Navigate<TViewModel, TParameter>(TParameter param, IMvxBundle presentationBundle = null) where TViewModel : IMvxViewModel<TParameter>;

Before you use this method, make sure the target ViewModel has a generic param, like PostDetailViewModel:

public class PostDetailViewModel : MvxViewModel<Post>
{
	…
}

For some situation, we need to get the result of the target ViewModel and return it to the source ViewModel. For example, if we edit a Post, we should update the post in the PostListView after returning.