Autofac asp.net MVC控制器和ViewModel

Question

I'm getting this error: [MissingMethodException: No parameterless constructor defined for this object. Object type 'MyProject.TestViewModel'.]

Global.asax.cs

var builder = new ContainerBuilder();
builder.RegisterControllers(typeof(MvcApplication).Assembly);
builder.RegisterType<MyProfileStore>().As<IMyProfileStore>();
builder.RegisterType<BreadCrumbImageService>().As<IBreadCrumbImageService>().SingleInstance();
builder.RegisterType<MyProfileViewModel>().As<IMyProfileViewModel>();
builder.RegisterType<BaseViewModel>().As<IBaseViewModel>();
builder.RegisterType<TestViewModel>().As<ITestViewModel>();
builder.RegisterType<TestSvc1>().As<ITestSvc>();
builder.RegisterType<TestSvc3>().As<ITestSvc>();
builder.RegisterType<TestSvc2>().As<ITestSvc>();
var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

Controller

public class MyAccountController : BaseController
{
    public ActionResult Test(TestViewModel testViewModel)
    {
        _testViewModel = testViewModel;
        return View(_testViewModel);
    }

ViewModel

public class TestViewModel : ITestViewModel 
{
    private TestSvc1 _testSvc1;
    public string ViewModelText { get; set; }

    public TestViewModel(TestSvc1 testSvc1)
    {
        _testSvc1 = testSvc1;
        ViewModelText = _testSvc1.GetText();
    }
}

Are there additional steps I need to take with this? I was expecting that once I had registered the builder.RegisterType().As(); I would be good to go. I have tried to do the injection at the controller level in that constructor, and it gives me

None of the constructors found with 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder' on type 'MyProject.MyAccountController' can be invoked with the available services and parameters:
Cannot resolve parameter 'MyProject.TestViewModel testViewModel' of constructor 'Void .ctor(MyProject.TestViewModel)'.

I'd like to stick with constructor injection, I don't know what I'm missing here.

Answer 1

You have a dependency on TestSvc1 , but no service is registered as that type. You have TestSvc1 registered as a ITestSvc , and only as that. If you want to instead inject TestSvc1 , you will need to add AsSelf() to its registration.

builder.RegisterType<TestSvc1>()
    .As<ITestSvc>()
    .AsSelf();

Or change your viewmodel so it accepts a ITestSvc . This is probably the preferred solution.