Unable to resolve dependency for generic repository using autofac

Question

I am working with .net core API and resolving my dependency using autofac. However somehow I am not able to resolve dependency for my Generic Repository.

Can someone guide what I have done wrong.

startup.cs

var builder = new ContainerBuilder();

builder.RegisterType<UnitOfWork>().As<IUnitOfWork>()
    .InstancePerLifetimeScope();

builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>()
.InstancePerLifetimeScope();

//This is the place which is not working for me
builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepository<>)).InstancePerLifetimeScope();

builder.RegisterAssemblyTypes(typeof(SizeRepository).Assembly)
    .Where(t => t.Name.EndsWith("Repository"))
    .AsImplementedInterfaces()
    .InstancePerLifetimeScope();

builder.RegisterAssemblyTypes(typeof(UserService).Assembly)
    .Where(t => t.Name.EndsWith("Service"))
    .AsImplementedInterfaces()
    .InstancePerLifetimeScope();

builder.Populate(services);
var container = builder.Build();
//Create the IServiceProvider based on the container.
return new AutofacServiceProvider(container);

UnitOfWork.cs

using System.Threading.Tasks;

namespace MakeTalk.Data.Infrastructure
{
public class UnitOfWork : IUnitOfWork
{
    #region Local variable

    private readonly IDatabaseFactory databaseFactory;
    private MakeTalkEntities dataContext;

    #endregion

    #region Constructor
    public UnitOfWork(IDatabaseFactory databaseFactory)
    {
        this.databaseFactory = databaseFactory;
    }
    #endregion

    #region Property
    protected MakeTalkEntities DataContext => dataContext ?? (dataContext = databaseFactory.Get());
    #endregion

    #region Methods
    /// <summary>
    /// Commit changes 
    /// </summary>
    /// <history>Created : 01-04-2018</history>
    public void Commit()
    {
        DataContext.SaveChanges();
    }
    /// <summary>
    /// Commit Async changes
    /// </summary>
    /// <returns></returns>
    /// <history>Created : 01-04-2018</history>
    public async Task<int> CommitAsync()
    {
        return await DataContext.SaveChangesAsync();
    }

    #endregion

}
}

Repository.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;


namespace MakeTalk.Data.Infrastructure
{
    public class Repository<T> : IRepository<T> where T : class
    {
        #region Variable / Properties  
        private MakeTalkEntities dataContext;
        private readonly DbSet<T> dbSet;
        protected MakeTalkEntities DataContext => dataContext ?? (dataContext = DatabaseFactory.Get());
    protected IDatabaseFactory DatabaseFactory
    {
        get;
        private set;
    }
    #endregion

    #region Constructor
    protected Repository(IDatabaseFactory databaseFactory)
    {
        DatabaseFactory = databaseFactory;
        dbSet = DataContext.Set<T>();
    }
    #endregion

    #region Sync Methods

    // all methods ...
    #endregion
}
}

DatabaseFactory.cs

using Microsoft.EntityFrameworkCore;

namespace MakeTalk.Data.Infrastructure
{
    public class DatabaseFactory : Disposable, IDatabaseFactory
    {
        private MakeTalkEntities dataContext;

        public MakeTalkEntities Get()
        {
            return dataContext ?? (dataContext = new MakeTalkEntities(new DbContextOptions<MakeTalkEntities>()));
        }
        protected override void DisposeCore()
        {
            dataContext?.Dispose();
        }
    }
}

MakeTalkEntities.cs

using Microsoft.EntityFrameworkCore;
using MakeTalk.Data.Configuration;
using MakeTalk.Model;

namespace MakeTalk.Data
{
    public class MakeTalkEntities : DbContext
    {
        #region Constructor

        public MakeTalkEntities(DbContextOptions options)
        {

        }

        #endregion

        #region DB Properties 
        // db sets 

        #endregion

        #region Methods

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {


            // ReSharper disable once AssignNullToNotNullAttribute
            optionsBuilder.UseSqlServer("Some-Connection");

            base.OnConfiguring(optionsBuilder);
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {

            // all configutaion 

            base.OnModelCreating(modelBuilder);
        }
        #endregion

    }
}

Is there anything wrong with code? I am able to resolver my other repository & services just facing issue with Generic Repository builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepository<>)).InstancePerLifetimeScope();

At time of using this generic repository I gets following error

Autofac.Core.DependencyResolutionException: An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = CommonService (ReflectionActivator), Services = [MakeTalk.Service.ICommonService], Lifetime = Autofac.Core.Lifetime.CurrentScopeLifetime, Sharing = Shared, Ownership = OwnedByLifetimeScope ---> An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = Repository 1 (ReflectionActivator), Services = [MakeTalk.Data.Infrastructure.IRepository 1[[MakeTalk.Model.ExhibitionRequestStatus, MakeTalk.Model, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]], Lifetime = Autofac.Core.Lifetime.CurrentScopeLifetime, Sharing = Shared, Ownership = OwnedByLifetimeScope ---> No constructors on type 'MakeTalk.Data.Infrastructure.Repository 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. (See inner exception for details.) (See inner exception for details.) ---> Autofac.Core.DependencyResolutionException: An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = Repository 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. (See inner exception for details.) (See inner exception for details.) ---> Autofac.Core.DependencyResolutionException: An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = Repository 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. (See inner exception for details.) (See inner exception for details.) ---> Autofac.Core.DependencyResolutionException: An error occurred during the activation of a particular registration. See the inner exception for details. Registration: Activator = Repository 1 (ReflectionActivator), Services = [MakeTalk.Data.Infrastructure.IRepository 1[[MakeTalk.Model.ExhibitionRequestStatus, MakeTalk.Model, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]], Lifetime = Autofac.Core.Lifetime.CurrentScopeLifetime, Sharing = Shared, Ownership = OwnedByLifetimeScope ---> No constructors on type 'MakeTalk.Data.Infrastructure.Repository 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. (See inner exception for details.) ---> Autofac.Core.DependencyResolutionException: No constructors on type 'MakeTalk.Data.Infrastructure.Repository 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. at Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable 1[MakeTalk.Model.ExhibitionRequestStatus]' can be found with the constructor finder 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder'. at Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable 1 parameters) at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable 1 parameters) --- End of inner exception stack trace --- at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable 1 parameters) at Autofac.Core.Lifetime.LifetimeScope.GetOrCreateAndShare(Guid id, Func 1 creator) at Autofac.Core.Resolving.InstanceLookup.Execute() at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable 1 parameters) at Autofac.Core.Activators.Reflection.ConstructorParameterBinding.Instantiate() at Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable 1 parameters) at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable 1 parameters) --- End of inner exception stack trace --- at Autofac.Core.Resolving.InstanceLookup.Act ivate(IEnumerable 1 parameters) at Autofac.Core.Lifetime.LifetimeScope.GetOrCreateAndShare(Guid id, Func 1 creator) at Autofac.Core.Resolving.InstanceLookup.Execute() at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable 1 parameters) at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable 1 parameters) at Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable 1 parameters, Object& instance) at Autofac.ResolutionExtensions.ResolveOptionalService(IComponentContext context, Service service, IEnumerable 1 parameters) at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired) at lambda_method(Closure , IServiceProvider , Object[] ) at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.< >c__DisplayClass4_0.b__0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.g__CreateController|0(ControllerContext controllerContext) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync() at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter() at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync() at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync() at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext) at Microsoft.AspNetCore.Routing.EndpointRoutingMi ddleware.Invoke(HttpContext httpContext) at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Answer 1

If you look at the error message you can see this

No constructors on type MakeTalk.Data.Infrastructure.Repository1[MakeTalk.Model.ExhibitionRequestStatus] can be found with the constructor finder Autofac.Core.Activators.Reflection.DefaultConstructorFinder .

it means that Autofac can't find a constructor on type Repository<T> . If you look at this type the constructor is marked as protected which means Autofac doesn't have access to it.

To fix this error you have to change the constructor to public