MVC5和Ninject：无参数构造函数错误

Question

在MVC 5中，我们获得了如下所示的帐户控制器。

public class AccountController : Controller
        {

            public AccountController()
                : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new DatePickerDbContext())))
            {

            }

            public AccountController(UserManager<ApplicationUser> userManager)
            {
                UserManager = userManager;
            }
        }

我安装了Ninject来处理依赖项注入。我有两个存储库，我想在我的AccountController中使用现在代码看起来像这样

    public class AccountController : Controller
    {
              private readonly ILicenserepository _licenserepository;
              private readonly IUserRepository _userRepository;    

        public AccountController(ILicenserepository licenserepository, IUserRepository userRepository)
            : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new DatePickerDbContext())))
        {
            _licenserepository = licenserepository;
            _userRepository = userRepository;
        }

        public AccountController(UserManager<ApplicationUser> userManager)
        {
            UserManager = userManager;
        }
    }

在ninject.web.com中，这是我所做的

private static void RegisterServices(IKernel kernel)
{
    kernel.Bind(typeof (ILicenserepository)).To(typeof (Licenserepository));
    kernel.Bind(typeof (IUserRepository)).To(typeof (UserRepository));
}    

但是当我运行应用程序时，我在浏览器上收到错误消息，提示未找到无参数构造函数。而且，如果我创建的参数少了构造函数，则不会实例化我的存储库。因此，无论我在存储库中调用该方法的何处，该值均为null。我怎么解决这个问题？还是让MVC或Ninject知道要调用哪个构造函数？

Answer 1

您需要在Global.asax.cs中注册的DependencyResolver

注册看起来像这样：

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();

    RegisterGlobalFilters(GlobalFilters.Filters);
    RegisterRoutes(RouteTable.Routes);
    RegisterDependencyResolver();
}

private void RegisterDependencyResolver()
{
    var kernel = new StandardKernel();

    // you may need to configure your container here?
    RegisterServices(kernel);

    DependencyResolver.SetResolver(new NinjectDependencyResolver(kernel));
}

和DependencyResolver

public class NinjectDependencyResolver : IDependencyResolver
{
    private readonly IKernel kernel;

    public NinjectDependencyResolver(IKernel kernel)
    {
        this.kernel = kernel;
    }

    public object GetService(Type serviceType)
    {
        return this.kernel.TryGet(serviceType);
    }

    public IEnumerable<object> GetServices(Type serviceType)
    {
        try
        {
            return this.kernel.GetAll(serviceType);
        }
        catch (Exception)
        {
            return new List<object>();
        }
    }
}

Answer 2

这是更新：如果您正在使用MVC5和WebAPI 2，则只需使用NuGet Manager并将NinjectMVC5和NinjectWebApi2添加到您的项目中。然后错误消失了。 （使用Visual Studio 2013）

欢呼声

Answer 3

我刚使用.NET MVC 5和Ninject 3.3.4即可正常工作。

已采取的步骤：

1. 安装Ninject 3.3.4
2. 安装Ninject.Web.Common 3.3.1
3. 安装Ninject.Web.Common.WebHost 3.3.1
4. 安装Ninject.MVC5 3.3.0（用于MVC Controller）

（（可选）Api控制器步骤

5. 安装Ninject.Web.WebApi 3.3.0（用于api ApiController）
6. 安装Ninject.Web.WebApi.WebHost（与ApiController一起使用]

这里的重要区别是您的项目是使用Api控制器还是Mvc控制器。如果您不熟悉其中的区别，请查看以下帖子：

Difference between ApiController and Controller in ASP.NET MVC。

[注：我确实需要对Ninject.Web.Common.cs文件进行任何额外的配置。下面是我的配置，省略了绑定]

[assembly: WebActivatorEx.PreApplicationStartMethod(typeof(YourProject.Web.App_Start.NinjectWebCommon), "Start")]
[assembly: WebActivatorEx.ApplicationShutdownMethodAttribute(typeof(YourProject.Web.App_Start.NinjectWebCommon), "Stop")]

namespace YourProject.Web.App_Start
{
    using System;
    using System.Web;
    using Microsoft.Web.Infrastructure.DynamicModuleHelper;
    using Ninject;
    using Ninject.Web.Common;
    using Ninject.Web.Common.WebHost;

    public static class NinjectWebCommon 
    {
        private static readonly Bootstrapper bootstrapper = new Bootstrapper();

        /// <summary>
        /// Starts the application
        /// </summary>
        public static void Start() 
        {
            DynamicModuleUtility.RegisterModule(typeof(OnePerRequestHttpModule));
            DynamicModuleUtility.RegisterModule(typeof(NinjectHttpModule));
            bootstrapper.Initialize(CreateKernel);
        }

        /// <summary>
        /// Stops the application.
        /// </summary>
        public static void Stop()
        {
            bootstrapper.ShutDown();
        }

        /// <summary>
        /// Creates the kernel that will manage your application.
        /// </summary>
        /// <returns>The created kernel.</returns>
        private static IKernel CreateKernel()
        {
            var kernel = new StandardKernel();
            try
            {
                kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);
                kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();
                RegisterServices(kernel);
                return kernel;
            }
            catch
            {
                kernel.Dispose();
                throw;
            }
        }

        /// <summary>
        /// Load your modules or register your services here!
        /// </summary>
        /// <param name="kernel">The kernel.</param>
        private static void RegisterServices(IKernel kernel)
        {
            // Common

            // Repositories

            // Services

            // Factories

            // Misc
        }        
    }
}