public BirthdayEditViewModel(
ICommandResolver commandResolver,
INavigationService navigationService,
IFileSystem fileService,
IMediaService mediaService,
IPlatformDocumentPicker documentPicker)
: base(navigationService)
{
_fileService = fileService;
_mediaService = mediaService;
SaveBirthdayCommand = commandResolver.AsyncCommand(SaveBirthday);
ChangePersonImageCommand = commandResolver.AsyncCommand(ChangePersonImage);
SelectMonthCommand = commandResolver.Command <BirthDateViewModel>(SelectMonth);
SelectDayCommand = commandResolver.Command <BirthdayDayViewModel>(SelectDay);
_documentPicker = documentPicker;
BirthDateViewModels = new RangeObservableCollection <BirthDateViewModel>();
InitializeDays();
SelectedBirthDateViewModel = BirthDateViewModels.ElementAt(0);
}