“no parameterless constructor defined for this object” error

Question

I am getting an error. I am using Moq and Ninject. Here are the detailed error message:

[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) +113
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) +66 System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +55

[InvalidOperationException: An error occurred when trying to create a controller of type 'EF.Controllers.ProductController'. Make sure that the controller has a parameterless public constructor.]
System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +179
System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +80
System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +74
System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +193 System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +49
System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +49
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +301 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Here is my Controller :

public class ProductController : Controller
{
    private IProductRepository repository;

    public ProductController(IProductRepository productRepository)
    {
        this.repository = productRepository;
    }

    public ViewResult List()
    {
        return View(repository.Products);
    }

}

RouteConfig points out the List ActionMethod. Here is the content of the IProductRepository:

public interface IProductRepository
{
    IQueryable<Product> Products { get; }
}

Here is the definition of the Product:

public class Product
{
    public int ProductID { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }
    public string Category { get; set; }
}

And here is the NinjectControllerFactory class:

public class NinjectControllerFactory : DefaultControllerFactory
{

    private IKernel ninjectKernel;

    public NinjectControllerFactory()
    {
        ninjectKernel = new StandardKernel();
        AddBindings();
    }

    protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        return controllerType == null
        ? null
        : (IController)ninjectKernel.Get(controllerType);
    }

    /// <summary>
    /// An binding has been implemented there. I am creating a Mock object, and I embedded it.
    /// </summary>
    private void AddBindings()
    {
        Mock<IProductRepository> mock = new Mock<IProductRepository>();

        mock.Setup(m => m.Products).Returns(new List<Product> {
        new Product { Name = "Football", Price = 25 },
        new Product { Name = "Surf board", Price = 179 },
        new Product { Name = "Running shoes", Price = 95 }
        }.AsQueryable());

        ninjectKernel.Bind<IProductRepository>().ToConstant(mock.Object);
    }
}

What I am missing? Could you please help me? Thanks in advance.

How did you register your NinjectControllerFactory in MVC? It seems from the stack trace that your custom controller factory isn't used at all. — Steven
@Steven is right. You probably didn't set correctly your factory: ControllerBuilder.Current.SetControllerFactory(typeof (NinjectControllerFactory ). Understanding and Extending Controller Factory in MVC — Old Fox
Steven, The Old Fox. You were right. In the Application_Start() I shall add the code : ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory()); After I wrote it, problem is solved. Your point is right. I can not accept your answers due to the web site. — tahasozgen

ryanulit ryanulit · Accepted Answer · 2016-04-08T14:54:15

Your use of Moq is incorrect. You don't use Moq for dependency injection, you use it for mocking an interface (ideally) when unit testing another class that has a dependency on that interface. You shouldn't even be using Moq in the NinjectControllerFactory.

Your AddBindings() method should simply be:

ninjectKernel.Bind<IProductRepository>().To<ProductRepository>();

Also, usually DI containers have a convention by default approach, which should allow you to not even need to use the Bind<>().To<>() statement there. I'm not as familiar with Ninject, but I will try to find a sample for you.

“no parameterless constructor defined for this object” error

1 Answers