未注册要在ViewModel中使用的服务
你好，我问这个绝望，因为我找不到一个解决方案。我正在做一个mvvm项目在wpf与依赖注入，我得到了这个类。

public class ObservableObject : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

public abstract class ViewModelCore:ObservableObject
    {

    }

public class NavigationService : ObservableObject, INavigationService
    {
        private ViewModelCore _currentView;
        private Func<Type, ViewModelCore> _viewModelFactory;

        public ViewModelCore CurrentView
        {
            get => _currentView;
            private set
            {
                _currentView = value;
                OnPropertyChanged();
            }
        }
        public NavigationService(Func<Type,ViewModelCore> viewModelFactory)
        {
            _viewModelFactory = viewModelFactory;
        }

         
        public void NavigateTo<TViewModel>() where TViewModel : ViewModelCore
        {
            ViewModelCore viewModel = _viewModelFactory.Invoke(typeof(TViewModel));
            CurrentView = viewModel;
        }

    }

public class MainViewModel:ViewModelCore
    {

        private INavigationService _navigation;
        public INavigationService Navigation
        {
            get => _navigation;
            set
            {
                _navigation = value;
                OnPropertyChanged();
            }
        }

        public RelayCommand NavigationHomeCommand { get; set; }
        public RelayCommand NavigationPatientListViewCommand { get; set; }
        public RelayCommand NavigationAppointmentsViewCommand { get; set; }
        public MainViewModel(INavigationService navService)
        {
            Navigation = navService;
            NavigationHomeCommand = new RelayCommand(o => true, o => { Navigation.NavigateTo<HomeViewModel>(); });
            NavigationPatientListViewCommand = new RelayCommand(o => true, o => { Navigation.NavigateTo<PatientListViewModel>(); });
            NavigationAppointmentsViewCommand = new RelayCommand(o => true, o => { Navigation.NavigateTo<AppointmentViewModel>(); });

        }
    }

public partial class App : Application
    {
        private ServiceProvider _serviceProvider;

        
        public App()
        {

            IServiceCollection services = new ServiceCollection();
            services.AddSingleton(
                provider => new MainWindow
                {
                    DataContext = provider.GetRequiredService<MainViewModel>()
                }
                );

            services.AddSingleton<MainViewModel>();
            services.AddSingleton<HomeViewModel>();
            services.AddSingleton<PatientListViewModel>();
            services.AddSingleton<AppointmentViewModel>();
            services.AddScoped<INavigationService, NavigationService>();
            services.AddScoped<IAppointmentService, AppointmentService>();
         

            services.AddSingleton<Func<Type, ViewModelCore>>(serviceProvider => viewModelType => (ViewModelCore)serviceProvider.GetRequiredService(viewModelType));

            _serviceProvider = services.BuildServiceProvider();
        }
        protected override void OnStartup(StartupEventArgs e)
        {
        
            var mainWindow = _serviceProvider.GetService<MainWindow>();
            mainWindow.Show();
            base.OnStartup(e);
        }

我得到这个错误消息：System.InvalidOperationException：“在尝试激活“Healthplss.Services. AppointmentService”时，无法解析类型“Healthplss. Services.GenericDataService”“1[Healthplss.Models.Appointment]”的服务。“尽管该服务在我的app.xaml.cs中重新注册，但我也在约会构造器视图模型中声明了要访问的DI容器，但它不允许我访问。”有人知道吗？先谢谢你。
Edit1：添加AppointmentService

public class AppointmentService:IAppointmentService
    {
        private readonly GenericDataService<Appointment> _genericDataService;

        public AppointmentService(GenericDataService<Appointment> genericDataService)
        {
            _genericDataService = genericDataService;
        }

        public async Task AddAppointmentAsync(Models.Appointment appointment)
        {
            await _genericDataService.Create(appointment);
        }

        public Task DeleteAppointmentAsync(int id)
        {
            throw new NotImplementedException();
        }

        public Task GetAppointmentById(int id)
        {
            throw new NotImplementedException();
        }

        public async Task<List<Models.Appointment>> GetAppointmentsAsync()
        {
            return await _genericDataService.GetAll();
        }

        public Task UpdateAppointmentAsync(Models.Appointment appointment)
        {
            throw new NotImplementedException();
        }
    }

我想在数据库中写入实体，所以我使用通用数据服务