AutoFac.Core.DependencyResolutionException after following tutorial

Question

New to Autofac, followed a tutorial on Youtube(with great ratings) but its throwing an exception, no idea why.

Exceptions:

DependencyResolutionException: An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = IDomainRepository (ReflectionActivator), Services = [Solution.Entities.IDomainRepository], Lifetime = Autofac.Core.Lifetime.CurrentScopeLifetime, Sharing = None, Ownership = OwnedByLifetimeScope

And

NoConstructorsFoundException: No accessible constructors were found for the type 'Solution.Entities.IDomainRepository'.

IDomainRepository

public interface IDomainRepository
{
    List<Domain> GetAll();

    string Insert(Domain obj);

    bool Update(Domain obj);

    bool Delete(string URL);
}

DomainRepository

public class DomainRepository : IDomainRepository
{
    public List<Domain> GetAll()
    {
        using (IDbConnection db = new SqlConnection(Helper.ConnectionString))
        {
            if (db.State == ConnectionState.Closed)
            {
                db.Open();
            }
            return db.Query<Domain>("SELECT * FROM Domains", commandType: CommandType.Text).ToList();

        }
    }

    public string Insert(Domain obj)
    {
        using (IDbConnection db = new SqlConnection(Helper.ConnectionString))
        {
            if (db.State == ConnectionState.Closed)
            {
                db.Open();
            }
            db.Query<Domain>("INSERT INTO Domains (Domain) VALUES ("+obj.URL+")", commandType: CommandType.Text);
            return obj.URL;

        }
    }

    public bool Update(Domain obj)
    {
        using (IDbConnection db = new SqlConnection(Helper.ConnectionString))
        {
            if (db.State == ConnectionState.Closed)
            {
                db.Open();
            }
            int result = db.Execute("UPDATE Domains SET Domain="+obj.URL+" WHERE Domain="+obj.URL+")", commandType: CommandType.Text);
            return result != 0;

        }
    }

    public bool Delete(string URL)
    {
        using (IDbConnection db = new SqlConnection(Helper.ConnectionString))
        {
            if (db.State == ConnectionState.Closed)
            {
                db.Open();
            }
            int result = db.Execute("delete from Domains where Domain = @Url", new { Url = URL }, commandType: CommandType.Text);
            return result != 0;
        }
    }
}

DomainHandler

static Autofac.IContainer _container;

    static DomainHandler()
    {
        ContainerBuilder builder = new ContainerBuilder();
        builder.RegisterType<IDomainRepository>().As<IDomainRepository>();
        _container = builder.Build();
    }

    public static bool Delete(string Url)
    {
        return _container.Resolve<IDomainRepository>().Delete(Url);
    }

    public static List<Domain> GetAll()
    {
        return _container.Resolve<IDomainRepository>().GetAll();
    }

    public static Domain Save(Domain obj, EntityState state)
    {
        if (state == EntityState.Added)
            obj.URL = _container.Resolve<IDomainRepository>().Insert(obj);
        else
            _container.Resolve<IDomainRepository>().Update(obj);

        return obj;
    }

Anyone know what might be causing this error? Read about forgetting to set public access on the interface but thats not the issue here.. :/

Solution 1

Anyone know what might be causing this error?

builder.RegisterType<IDomainRepository>().As<IDomainRepository>();
                     ^^

should be

builder.RegisterType<DomainRepository>().As<IDomainRepository>();
                     ^

because you need to RegisterType of the Concrete type, not the interface.

Autofac Registration Concepts

Excerpt:

Any component type you register via RegisterType must be a concrete type.

Solution 2

I know that the question was resolved. But I had the same error and it was from a different source.

My registered class had a constructor in which a service is injected. This service was not registered.

All dependency chain needs to be registered.

Comments

[itcoder]

Hi @ihebiheb, did you manage to resolve this issue? I think I am having a similar one now.

[ihebiheb]

yes. This error says that you have some classes that aren't known by autofac. So you need to register all the classes that need to be injected AND ALL their dependencies. Example if your injected class has a service injected in its constructor, you need to inject it too. if this last class have an other service injected in its constructor, you need to inject it too also.

[itcoder]

Mmm that makes sense, I've put this part of my project to the side for now. But thats good insight when I pick it up again later. Thanks!