Asp.net核心通用存储库模式，继承不起作用

Question

I have created a generic repository class and interface which will be subclassed for the concrete repositories.

Here is some of my code:

The generic IRepository interface and Repository class:

public interface IRepository<T> where T : BaseEntity
{
    IEnumerable<T> GetAll();
    T Get(long id);
    void Insert(T entity);
    void Update(T entity);
    void Delete(T entity);
}

public class Repostitory<T> : IRepository<T> where T : BaseEntity
    {
        protected readonly ApplicationDbContext _context;
        private DbSet<T> _entities;
        private string errorMessage = string.Empty;

        public Repostitory(ApplicationDbContext context)
        {
            this._context = context;
            _entities = context.Set<T>();
        }

        public IEnumerable<T> GetAll()
        {
            return _entities.AsEnumerable();
        }

        public T Get(long id)
        {
            return _entities.SingleOrDefault(s => s.Id == id);
        }

        public void Insert(T entity)
        {
            CheckEntityNotNull(entity);
            _entities.Add(entity);
            _context.SaveChanges();
        }

        public void Update(T entity)
        {
            CheckEntityNotNull(entity);
            _context.SaveChanges();
        }

        public void Delete(T entity)
        {
            CheckEntityNotNull(entity);
            _entities.Remove(entity);
            _context.SaveChanges();
        }

        private void CheckEntityNotNull(T entity)
        {
            if(entity == null)
            {
                throw new ArgumentNullException("Entity");
            }
        }
    }

Inherited Interface and class:

public interface IEventsRepository : IRepository<Event>
{

}

public class EventsRepository : Repostitory<Event>
{
    public EventsRepository(ApplicationDbContext context) : base(context)
    {

    }
}

At this moment there is no implementation yet in IEventsRepository and EventsRepository , but there will be once I got this to work.

In Startup.cs I have this in the ConfigureServices method

public void ConfigureServices(IServiceCollection services)
{
    // Add framework services.
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
    services.AddScoped(typeof(IRepository<>), typeof(Repostitory<>));
    services.AddScoped(typeof(IEventsRepository), typeof(EventsRepository));
}

And in the controller:

public class AdminController : Controller
{
    private readonly IEventsRepository _eventsRepository;

    public AdminController(IEventsRepository eventsRepository)
    {
        _eventsRepository = eventsRepository;
    }

    [HttpGet]
    public IActionResult EventsIndex()
    {
        var model = _eventsRepository.GetAll();
        return View(model);
    }
}

When building the application I do not get any errors, or even when I open the homepage.

When I open the EventsIndex page an internal server error is raised:

InvalidCastException: Unable to cast object of type 'WebsiteProject.Repositories.EventsRepository`1[WebsiteProject.Models.Event]' to type 'WebsiteProject.Repositories.IEventsRepository`1[WebsiteProject.Models.Event]'.

What am I missing here?

Answer 1

I was able to fix it. It was quite simple actually.

All I had to do is make EventsRepository also implement IEventsRepository .

So instead of

public class EventsRepository : Repostitory<Event>
{
    public EventsRepository(ApplicationDbContext context) : base(context)
    {

    }
}

I changed it to:

public class EventsRepository : Repostitory<Event>, IEventsRepository
{
    public EventsRepository(ApplicationDbContext context) : base(context)
    {

    }
}