公寓管理费系统注入IUnitOfWork到ApartmentManager遇Autofac依赖错误

错误信息 #

Autofac.Core.DependencyResolutionException: An exception was thrown while activating Business.Concrete.ApartmentManager -> DataAccess.Concrete.UnitOfWork.UnitOfWork.

---> Autofac.Core.DependencyResolutionException: None of the constructors found on type 'DataAccess.Concrete.UnitOfWork.UnitOfWork' can be invoked with the available services and parameters:

Cannot resolve parameter 'DataAccess.Concrete.EntityFramework.Context.ApartmentDuesManagementContext context' of constructor 'Void .ctor(DataAccess.Concrete.EntityFramework.Context.ApartmentDuesManagementContext)'.

问题背景 #

开发公寓管理费管理系统时，尝试将IUnitOfWork注入到ApartmentManager的构造函数中时触发上述错误。移除IUnitOfWork参数后错误消失，但无法使用工作单元模式实现批量提交（比如一次性插入100条记录），需要解决依赖注入问题。

相关代码 #

Autofac注册模块 #

public class AutofacBusinessModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        builder.RegisterType<UnitOfWork>().As<IUnitOfWork>()
            .InstancePerLifetimeScope();
        builder.RegisterType<EfApartmentDal>().As<IApartmentDal>()
            .InstancePerLifetimeScope();
        builder.RegisterType<ApartmentManager>()
            .As<IApartmentService>()
            .InstancePerLifetimeScope();
    }
}

IUnitOfWork接口 #

public interface IUnitOfWork
{
    Task CommitAsync();
    void Commit();
    //Task<int> SaveChangesAsync();
    //Task BeginTransactionAsync();
    //Task CommitTransactionAsync();
    //Task RollbackTransactionAsync();

    //public interface IEntityRepository<T> where T : class, IEntity, new()
    //{
    //    Task AddRangeAsync(IEnumerable<T> entities);
    //}

    //public interface IApartmentRepository : IEntityRepository<Apartment> { }
}

UnitOfWork实现类 #

public class UnitOfWork : IUnitOfWork
{
    private readonly ApartmentDuesManagementContext _context;
    //private IDbContextTransaction _transaction;
    public UnitOfWork(ApartmentDuesManagementContext context)
    {
        _context = context;
    }
    public void Commit()
    {
        _context.SaveChanges();
    }

    public async Task CommitAsync()
    {
        await _context.SaveChangesAsync();
    }
}

EfApartmentDal实现类 #

public class EfApartmentDal : EfEntityRepositoryBase<Apartment, ApartmentDuesManagementContext>, IApartmentDal
{
   
}

IApartmentDal接口 #

public interface IApartmentDal : IEntityRepository<Apartment>
{
    
}

IApartmentService接口 #

public interface IApartmentService
{
    IDataResult<List<Apartment>> GetList();
    Task<IDataResult<Task<IEnumerable<Apartment>>>> AddRangeAsync<TEntity>(IEnumerable<Apartment> apartments);
}

ApartmentManager实现类 #

public class ApartmentManager : IApartmentService
{
    private readonly IApartmentDal _apartmentDal;
    private readonly IUnitOfWork _unitOfWork;
    public ApartmentManager(IApartmentDal apartmentDal, IUnitOfWork unitOfWork)
    {
        _apartmentDal = apartmentDal;
        _unitOfWork = unitOfWork;
    }

    public IDataResult<List<Apartment>> GetList()
    {
        return new SuccessDataResult<List<Apartment>>(_apartmentDal.GetList(), "Apartmanlar basarili bir sekilde listelendi.");
    }

    public async Task<IDataResult<Task<IEnumerable<Apartment>>>> AddRangeAsync<TEntity>(IEnumerable<Apartment> apartments)
    {
        await _apartmentDal.AddRangeAsync(apartments);
        await _unitOfWork.CommitAsync();
        return new SuccessDataResult<Task<IEnumerable<Apartment>>>(Task.FromResult(apartments), "Kayıt ekleme başarılı");
    }
}

解决方案 #

1. 注册DbContext到Autofac容器 #

错误的核心原因是Autofac容器中没有注册ApartmentDuesManagementContext，导致无法解析UnitOfWork构造函数中的上下文参数。需要在AutofacBusinessModule的Load方法中添加DbContext的注册：

public class AutofacBusinessModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        // 注册DbContext，生命周期和其他服务保持一致
        builder.RegisterType<ApartmentDuesManagementContext>()
            .InstancePerLifetimeScope();
            
        builder.RegisterType<UnitOfWork>().As<IUnitOfWork>()
            .InstancePerLifetimeScope();
        builder.RegisterType<EfApartmentDal>().As<IApartmentDal>()
            .InstancePerLifetimeScope();
        builder.RegisterType<ApartmentManager>()
            .As<IApartmentService>()
            .InstancePerLifetimeScope();
    }
}

2. 确保上下文实例共享 #

使用InstancePerLifetimeScope可以保证在同一个请求/生命周期范围内，EfApartmentDal和UnitOfWork拿到的是同一个ApartmentDuesManagementContext实例，这样调用AddRangeAsync添加多条记录后，通过UnitOfWork.CommitAsync()就能一次性提交所有变更，符合工作单元的设计意图。

3. 优化冗余泛型（可选） #

你的AddRangeAsync<TEntity>方法中的泛型参数TEntity没有实际使用，可以移除它简化代码：

public async Task<IDataResult<IEnumerable<Apartment>>> AddRangeAsync(IEnumerable<Apartment> apartments)
{
    await _apartmentDal.AddRangeAsync(apartments);
    await _unitOfWork.CommitAsync();
    return new SuccessDataResult<IEnumerable<Apartment>>(apartments, "Kayıt ekleme başarılı");
}

对应的接口也需要修改：

public interface IApartmentService
{
    IDataResult<List<Apartment>> GetList();
    Task<IDataResult<IEnumerable<Apartment>>> AddRangeAsync(IEnumerable<Apartment> apartments);
}

内容的提问来源于stack exchange，提问作者nikki