获取参数 public 构造函数错误

Question

An error occurred when trying to create a controller of type 'ChatBotController'. Make sure that the controller has a parameterless public constructor.

at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType) ↵ at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request) ↵ at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__15.MoveNext()

当我尝试访问我的 IFeedbackRepository 时，我收到错误提示。当我在 ChatBotController.cs

中放入构造函数时，就会发生这种情况

public class ChatBotController : ApiController
{
    IFeedbackRepository _feedbackRepository;
    public ChatBotController(IFeedbackRepository feedbackRepository)
    {
        _feedbackRepository = feedbackRepository;
    }

    [HttpPost]
    public IHttpActionResult PostQuestion([FromBody]string message) //TODO: make sure that webapi will search the message in the body of the http request
    {
        throw new NotImplementedException();
    }
}

我同时使用 MVC 和 Api，我都在我的 Global.asax:

中解决了这两个问题

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    GlobalConfiguration.Configure(WebApiConfig.Register);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);

    DependencyConfig.RegisterWebApiDependencies();
    DependencyConfig.RegisterMvcDependencies();
}

这是我的 DependencyConfig.cs MVC 和 Api:

public static void RegisterWebApiDependencies()
{
    var container = new Container();
    container.Options.DefaultScopedLifestyle = new AsyncScopedLifestyle();

    container.Register<IAnswerGenerator, PxlAnswerGenerator>(Lifestyle.Scoped);
    container.Register<ChatBotDbContext>(Lifestyle.Scoped);
    container.Register<IFeedbackRepository, FeedbackDbRepository>(Lifestyle.Scoped);

    container.Verify();

    DependencyResolver.SetResolver(new SimpleInjectorDependencyResolver(container));

}

public static void RegisterMvcDependencies()
{
    var container = new Container();

    container.Options.DefaultScopedLifestyle = new WebRequestLifestyle();

    container.Register<IFeedbackRepository, FeedbackDbRepository>(Lifestyle.Scoped);
    container.Register<ChatBotDbContext>(Lifestyle.Scoped);

    container.RegisterMvcControllers(Assembly.GetExecutingAssembly());

    container.Verify();

    DependencyResolver.SetResolver(new SimpleInjectorDependencyResolver(container));
}

我做错了什么？

Answer 1

根据 documentation of Simple-Injector 当你想为你注册的 WebApi 部分初始化解析器时你需要调用

container.RegisterWebApiControllers(GlobalConfiguration.Configuration);
container.Verify();
DependencyResolver.SetResolver(new SimpleInjectorWebApiDependencyResolver(container));

Answer 2

我没看到你打电话给 container.RegisterWebApiControllers(GlobalConfiguration.Configuration);在 RegisterWebApiDependencies() 中。这是必需的。

您可能想在此处查看与 ASP.NET Web API 和 MVC 集成的 simpleinjector 文档：

https://simpleinjector.readthedocs.io/en/latest/webapiintegration.html

此外，上面的文档在 application_start() 的开头有 container/DI 设置。如果上述更改单独不起作用，您可能想尝试将以下两行放在 application_start() 的开头：

DependencyConfig.RegisterWebApiDependencies(); DependencyConfig.RegisterMvcDependencies();

获取参数 public 构造函数错误

Getting parameterles public constructor error

.net

asp.net

simple-injector