没有在MVc5回购模式中为此对象定义无参数构造函数

Question

I am Having this issue

No parameterless constructor defined for this object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.MissingMethodException: No parameterless constructor defined for this object.

I am create a new project in mvc and used Layered architecture for data and repository. so when i called account controller i ZGit this error

This is My Code :- of Account Controller

public class AccountController : Controller
    {
        private readonly IAuthentication repositoryIAuthentication;
        private readonly IUserRepository repositoryUser;
        private readonly IPostRepository repositoryPost;
        private readonly ICommentRepository repositoryComment;
        private readonly ICategoryRepository repositoryCategory;
        private readonly MembershipProvider repositoryMemberShipProvider;
        private readonly IDEncryptionRepository repositoryDEncryption;
        private readonly IEmailSettingRepository repositoryEmailSetting;
        private readonly ISettingRepository repositorySetting;
        public AccountController(IUserRepository repoUser,
                                 IAuthentication repoIAuthentication,
                                 IPostRepository repoPost,
                                 ICommentRepository repoComment,
                                 ICategoryRepository repoCategory,
                                 MembershipProvider repoMemberShipProvider,
                                 IDEncryptionRepository repoDEncryption,
                                 IEmailSettingRepository repoEmailSetting,
                                 ISettingRepository repoSetting)
        {
            repositoryUser = repoUser;
            repositoryIAuthentication = repoIAuthentication;
            repositoryCategory = repoCategory;
            repositoryComment = repoComment;
            repositoryPost = repoPost;
            repositoryMemberShipProvider = repoMemberShipProvider;
            repositoryDEncryption = repoDEncryption;
            repositoryEmailSetting = repoEmailSetting;
            repositorySetting = repoSetting;
        }

This is the detailed error which shows on page : -

[MissingMethodException: No parameterless constructor defined for this object.] System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +119
System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +232 System.Activator.CreateInstance(Type type, Boolean nonPublic) +83 System.Activator.CreateInstance(Type type) +11 System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +55

[InvalidOperationException: An error occurred when trying to create a controller of type 'WebAppBlog.Controllers.AccountController'. Make sure that the controller has a parameterless public constructor.]
System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +178
System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +76
System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +88
System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +194 System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +50
System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +48
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +103 System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +159

Answer 1

I suspect the issue lies with the huge amount of dependencies your controller has. One of the repositories probably has a dependency which has not been registered with your container.

I would look into the unit of work pattern and if using Entity Framework use it's dbcontext (which implements the unit of work pattern). Or even better abstract to an IAccountService and in the implementation use the unit of work pattern there.