public MainViewModel(Library library, INavigator navigator, ILibraryStore store, IChangeTracker changeTracker)
: base(library)
{
Ensure.NotNull(navigator, "navigator");
Ensure.NotNull(changeTracker, "changeTracker");
changeTracker.Added += () => HasChange = true;
changeTracker.Cleared += () => HasChange = false;
Create = new DelegateCommand(() => navigator.CreateMovieAsync(library));
Edit = new EditMovieCommand(library, navigator);
Delete = new DeleteMovieCommand(library.Movies, navigator, changeTracker);
Save = new SaveCommand(library, store);
OpenConfiguration = new DelegateCommand(() => navigator.LibraryConfigurationAsync(library));
}