public override void OnNavigatedTo(NavigatedToEventArgs e, Dictionary <string, object> viewModelState)
        {
            base.OnNavigatedTo(e, viewModelState);

            if (!_isInitialized)
            {
                _isInitialized = true;
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
                FictionListViewModel.InitializeViewModelAsync();
                AuthorsListViewModel.InitializeViewModelAsync();
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
            }
        }
 public MainPageViewModel(INavigationService navigationService,
                          ISessionStateService sessionStateService,
                          NewsListViewModel newsListViewModel,
                          FictionListViewModel fictionListViewModel,
                          AuthorsListViewModel authorsListViewModel,
                          CommonViewModel commonViewModel)
 {
     _sessionStateService  = sessionStateService;
     _fictionListViewModel = fictionListViewModel;
     _navigationService    = navigationService;
     _authorsListViewModel = authorsListViewModel;
     _newsListViewModel    = newsListViewModel;
     _commonViewModel      = commonViewModel;
     ViewDetailsCommand    = new DelegateCommand <NewsItem>(ViewDetailsExecute);
     RefreshTabCommand     = new DelegateCommand(RefreshExecute);
 }