public CalendarViewModel(bool isMultipleSelect, DateTime initDate) { _calendar = new CalendarModel(initDate, isMultipleSelect); PriorCommand = new Command(() => { _calendar.PriorMonth(); PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(YearMonthLabel))); PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelectedDates))); RefreshChanges(); }); NextCommand = new Command(() => { _calendar.NextMonth(); PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(YearMonthLabel))); PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelectedDates))); RefreshChanges(); }); }