public NotificationViewModel(TvDbSeriesRepository repository, ReminderService reminderService)
        {
            this.repository      = repository;
            this.reminderService = reminderService;

            if (!IsInDesignMode)
            {
                MessengerInstance.Register <TvDbSeries>(this, s => Series = s);
            }

            applyCommand = new RelayCommand(async() =>
            {
                series.NotificationTime = NotificationTime;
                series.RemindersEnabled = remindersEnabled;
                var saveTask            = repository.SaveAsync(series);
                reminderService.CreateOrUpdateRemindersAsync(); //do not await, does not affect UI, can happen in the background
                await saveTask;
                MessengerInstance.Send(new Action <Frame>(a => a.GoBack()));
            });
        }