c# - Unity Bootstrapper (Unity.Mvc), Unity 3, MVC 5, EF6 接收错误 : Parameterless Public Constructor on Controller

Question

好吧，在谷歌、这里和几个 ASP/MVC 论坛上搜索之后，我一定要问我到底做错了什么。

我的应用程序有一个良好的开端，对 DI、IoC 有很好的理解，并且正在使用 Repository、Service 和 UnitOfWork 模式。当我尝试从 Unity 加载需要 DI 的 Controller 时，就好像 unity 没有解析任何已注册的项目，或者我做得不好。从我可以看到的这个版本的所有示例(不是创建 Bootstrap.cs 文件然后从 Global.asax 调用的版本)我正在做其他人所做的事情，而没有 Unity 的支持。

我的核心问题是:我是否已设置/配置 Unity 以根据需要将项目注入(inject) Controller 构造函数。如果我有，为什么它不像我看到的例子那样工作有什么想法吗？

我不断收到 AssetController 需要具有无参数公共(public)构造函数的错误。如果我添加一个，它会在没有 DI 的情况下使用它，如果我不添加一个，它就会大喊没有它。

谢谢，下面的代码。

UnityConfig.cs

namespace CARS.web.App_Start
{
    /// <summary>
    /// Specifies the Unity configuration for the main container.
    /// </summary>
    public class UnityConfig
    {
        #region Unity Container
        private static Lazy<IUnityContainer> container = new Lazy<IUnityContainer>(() =>
        {
            var container = new UnityContainer();
            RegisterTypes(container);
            return container;
        });

        /// <summary>
        /// Gets the configured Unity container.
        /// </summary>
        public static IUnityContainer GetConfiguredContainer()
        {
            return container.Value;
        }
        #endregion

        /// <summary>Registers the type mappings with the Unity container.</summary>
        /// <param name="container">The unity container to configure.</param>
        /// <remarks>There is no need to register concrete types such as controllers or API controllers (unless you want to 
        /// change the defaults), as Unity allows resolving a concrete type even if it was not previously registered.</remarks>
        public static void RegisterTypes(IUnityContainer container)
        {
            // NOTE: To load from web.config uncomment the line below. Make sure to add a Microsoft.Practices.Unity.Configuration to the using statements.
            // container.LoadConfiguration();

            // TODO: Register your types here
            // container.RegisterType<IProductRepository, ProductRepository>();
            container.RegisterType<IDataContext, CARSDEMOContext>(new PerRequestLifetimeManager())
                .RegisterType<IAssetService, AssetService>()
                .RegisterType<IUnitOfWork, UnitOfWork>()
                .RegisterType<IRepository<Asset>, Repository<Asset>>();
                //.RegisterType<AssetController>(new InjectionConstructor(typeof(IAssetService), typeof(IUnitOfWork)));
        }
    }
}

AssetController.cs(我正在执行注入(inject)参数的构造函数部分)

namespace CARS.web.Controllers
{
    public class AssetController : Controller
    {
        private readonly IAssetService _assetService;
        private readonly IUnitOfWork _unitOfWork;

        public AssetController(IAssetService assetService, IUnitOfWork unitOfWork)
        {
            _assetService = assetService;
            _unitOfWork = unitOfWork;
        }
        //other methods for CRUD etc stripped for brevity
    }
}

IAssetService.cs(第一个参数是 assetService )

namespace CARS.service
{
    public interface IAssetService : IService<Asset>
    {
        Task<IEnumerable<Asset>> GetAsync();
        Task<Asset> FindAsync(Guid id);
        Asset Add(Asset asset);
        Asset Update(Asset asset);
        void Remove(Guid id);
    }
}

AssetService.cs(IAssetService交互的具体实现)

namespace CARS.service
{


    public class AssetService : Service<Asset>, IAssetService
    {
        private readonly IRepositoryAsync<Asset> _repository;

        public AssetService(IRepositoryAsync<Asset> repository) : base(repository)
        {
            _repository = repository;
        }

        public Task<IEnumerable<Asset>> GetAsync()
        {
            //return _repository.Query().SelectAsync();
            return _repository.Query().SelectAsync();
        }

        public Task<Asset> FindAsync(Guid id)
        {
            return _repository.FindAsync(id);
        }

        public Asset Add(Asset asset)
        {
            _repository.Insert(asset);
            return asset;
        }

        public Asset Update(Asset asset)
        {
            _repository.Update(asset);
            return asset;
        }

        public void Remove(Guid id)
        {
            _repository.Delete(id);
        }
    }

}

IUnitOfWork.cs(这是来自 Long Le 的 Generic UofW and Repository - http://genericunitofworkandrepositories.codeplex.com/)

namespace Repository.Pattern.UnitOfWork
{
    public interface IUnitOfWork : IDisposable
    {
        int SaveChanges();
        Task<int> SaveChangesAsync();
        void Dispose(bool disposing);
        IRepository<TEntity> Repository<TEntity>() where TEntity : IObjectState;
        void BeginTransaction();
        bool Commit();
        void Rollback();
    }
}

UnitOfWork.cs(同样来自龙乐的框架)

namespace Repository.Pattern.Ef6
{
    public class UnitOfWork : IUnitOfWork, IUnitOfWorkAsync
    {
        #region Private Fields

        private readonly IDataContextAsync _dataContext;
        private bool _disposed;
        private ObjectContext _objectContext;
        private Dictionary<string, object> _repositories;
        private DbTransaction _transaction;

        #endregion Private Fields

        #region Constuctor/Dispose

        public UnitOfWork(IDataContextAsync dataContext)
        {
            _dataContext = dataContext;
        }

        public void Dispose()
        {
            if (_objectContext != null && _objectContext.Connection.State == ConnectionState.Open)
                _objectContext.Connection.Close();

            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public virtual void Dispose(bool disposing)
        {
            if (!_disposed && disposing)
                _dataContext.Dispose();
            _disposed = true;
        }

        #endregion Constuctor/Dispose

        public int SaveChanges()
        {
            return _dataContext.SaveChanges();
        }

        public IRepository<TEntity> Repository<TEntity>() where TEntity : IObjectState
        {
            return RepositoryAsync<TEntity>();
        }

        public Task<int> SaveChangesAsync()
        {
            return _dataContext.SaveChangesAsync();
        }

        public Task<int> SaveChangesAsync(CancellationToken cancellationToken)
        {
            return _dataContext.SaveChangesAsync(cancellationToken);
        }

        public IRepositoryAsync<TEntity> RepositoryAsync<TEntity>() where TEntity : IObjectState
        {
            if (_repositories == null)
                _repositories = new Dictionary<string, object>();

            var type = typeof (TEntity).Name;

            if (_repositories.ContainsKey(type))
                return (IRepositoryAsync<TEntity>) _repositories[type];

            var repositoryType = typeof (Repository<>);
            _repositories.Add(type, Activator.CreateInstance(repositoryType.MakeGenericType(typeof (TEntity)), _dataContext, this));

            return (IRepositoryAsync<TEntity>) _repositories[type];
        }

        #region Unit of Work Transactions

        public void BeginTransaction()
        {
            _objectContext = ((IObjectContextAdapter) _dataContext).ObjectContext;
            if (_objectContext.Connection.State != ConnectionState.Open)
            {
                _objectContext.Connection.Open();
                _transaction = _objectContext.Connection.BeginTransaction();
            }
        }

        public bool Commit()
        {
            _transaction.Commit();
            return true;
        }

        public void Rollback()
        {
            _transaction.Rollback();
            ((DataContext)_dataContext).SyncObjectsStatePostCommit();
        }

        #endregion

        // Uncomment, if rather have IRepositoryAsync<TEntity> IoC vs. Reflection Activation
        //public IRepositoryAsync<TEntity> RepositoryAsync<TEntity>() where TEntity : EntityBase
        //{
        //    return ServiceLocator.Current.GetInstance<IRepositoryAsync<TEntity>>();
        //}
    }
} 

已更新以包含来自 UnityMvcActivator.cs 的 SetResolver 信息

using System.Linq;
using System.Web.Mvc;
using Microsoft.Practices.Unity.Mvc;

[assembly: WebActivatorEx.PreApplicationStartMethod(typeof(CARS.web.App_Start.UnityWebActivator), "Start")]

namespace CARS.web.App_Start
{
    /// <summary>Provides the bootstrapping for integrating Unity with ASP.NET MVC.</summary>
    public static class UnityWebActivator
    {
        /// <summary>Integrates Unity when the application starts.</summary>
        public static void Start() 
        {
            var container = UnityConfig.GetConfiguredContainer();

            FilterProviders.Providers.Remove(FilterProviders.Providers.OfType<FilterAttributeFilterProvider>().First());
            FilterProviders.Providers.Add(new UnityFilterAttributeFilterProvider(container));

            DependencyResolver.SetResolver(new UnityDependencyResolver(container));

            // TODO: Uncomment if you want to use PerRequestLifetimeManager
             Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(UnityPerRequestHttpModule));
        }
    }
}

我已经阅读/尝试了以下信息/数据，但没有任何解决办法:

The type IUserStore`1 does not have an accessible constructor

How to add MVC 5 authentication to Unity IoC?

Types not resolving with Unity [MVC 5]

我已经准备好必须为 Unity 编写一个 ControllerFactory 才能做到这一点，但是当我发现的所有示例都只注册了配置并且注入(inject)显然发生在 Controller 上时，这似乎需要大量工作和其他需要的类。

最后是错误:

The following server error was encountered: 
An error occurred when trying to create a controller of type           'CARS.web.Controllers.AssetController'. Make sure that the controller has a parameterless     public constructor.Details are: 
at     System.Web.Mvc.DefaultControllerFactory.DefaultControllerActivator.Create(RequestContext    requestContext, Type controllerType) at    System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext,     String controllerName) at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase     httpContext, IController& controller, IControllerFactory& factory) at     System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback     callback, Object state) at     System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionSte    p.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&     completedSynchronously)

谢谢

Answer 1

您需要设置 DependencyResolver。我看不到您提供的示例中的代码。

设置 UnityContainer 并注册类型后，您需要设置 System.Web.MVC.DependencyResolver。

 DependencyResolver.SetResolver(new UnityDependencyResolver(container));