仅在第一个Web请求时抛出Ninject.ActivationException(WebAPI 2,OWIN 3,Ninject 3)

Question

我正在尝试创建一个"准系统"Web API项目,该项目使用OWIN中间件,Ninject Depencency Injection,最终将在IIS中托管.我按照文章"与ASP.NET Web.API2,OWIN和Ninject建立联系"中的说明进行了操作:http://www.alexzaitzev.pro/2014/11/webapi2-owin-and-ninject.html,除了我使用了一个空的Web应用程序项目,并且在创建项目时没有勾选"包含Web API引用和文件夹".

当我启动新API并发出页面请求时,我会Ninject.ActivationException抛出以下内容:

Server Error in '/' Application.

Error activating HttpConfiguration
More than one matching bindings are available.
Matching bindings:
 1) binding from HttpConfiguration to method
 2) binding from HttpConfiguration to constant value
Activation path:
 1) Request for HttpConfiguration

Suggestions:
 1) Ensure that you have defined a binding for HttpConfiguration only once.

刷新浏览器时,此异常消失了.我真的不明白是什么导致了这个异常.从我的观点来看,在OWIN环境和Ninject中对WebAPI缺乏经验,很难知道问题出在哪里.与Ninject一起......？它在OWIN ......？是在WebAPI ......？

这是我的Startup.cs文件的内容:

using System.Web.Http;
using LHD.API_2;
using Microsoft.Owin;
using Microsoft.Owin.Security.OAuth;
using Ninject.Web.Common.OwinHost;
using Ninject.Web.WebApi.OwinHost;
using Owin;

[assembly: OwinStartup(typeof(Startup))]

namespace LHD.API_2
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            HttpConfiguration config = new HttpConfiguration();

            // Web API configuration and services
            // Configure Web API to use only bearer token authentication.
            config.SuppressDefaultHostAuthentication();
            config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));

            // Web API routes
            config.MapHttpAttributeRoutes();
            config.Routes.MapHttpRoute("API Default", "api/1/{controller}/{action}/{id}", new { id = RouteParameter.Optional });

            app.UseNinjectMiddleware(() => NinjectConfig.CreateKernel.Value);
            app.UseNinjectWebApi(config);
        }
    }
}

这是我的NinjectConfig.cs文件的内容:

using System;
using System.Reflection;
using Ninject;

namespace LHD.API_2
{
    public static class NinjectConfig
    {
        public static Lazy<IKernel> CreateKernel = new Lazy<IKernel>(() =>
        {
            StandardKernel kernel = new StandardKernel();
            kernel.Load(Assembly.GetExecutingAssembly());

            RegisterServices(kernel);

            return kernel;
        });

        private static void RegisterServices(KernelBase kernel)
        {
            // TODO - put in registrations here...

            //kernel.Bind<IFakeService>().To<FakeService>();
        }
    }
}

这是我的packages.config的内容:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Microsoft.AspNet.WebApi" version="5.0.0" targetFramework="net451" />
  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.3" targetFramework="net451" />
  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.3" targetFramework="net451" />
  <package id="Microsoft.AspNet.WebApi.Owin" version="5.2.3" targetFramework="net451" />
  <package id="Microsoft.AspNet.WebApi.WebHost" version="5.0.0" targetFramework="net451" />
  <package id="Microsoft.Owin" version="3.0.1" targetFramework="net451" />
  <package id="Microsoft.Owin.Host.SystemWeb" version="3.0.1" targetFramework="net451" />
  <package id="Newtonsoft.Json" version="6.0.4" targetFramework="net451" />
  <package id="Ninject" version="3.2.0.0" targetFramework="net451" />
  <package id="Ninject.Extensions.ContextPreservation" version="3.2.0.0" targetFramework="net451" />
  <package id="Ninject.Extensions.NamedScope" version="3.2.0.0" targetFramework="net451" />
  <package id="Ninject.Web.Common" version="3.2.0.0" targetFramework="net451" />
  <package id="Ninject.Web.Common.OwinHost" version="3.2.3.0" targetFramework="net451" />
  <package id="Ninject.Web.WebApi" version="3.2.0.0" targetFramework="net451" />
  <package id="Ninject.Web.WebApi.OwinHost" version="3.2.4.0" targetFramework="net451" />
  <package id="Owin" version="1.0" targetFramework="net451" />
</packages>

...而且,为了完整起见,我的web.config的内容同样不引人注目:

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
    <system.web>
        <compilation debug="true" targetFramework="4.5.1" />
        <httpRuntime targetFramework="4.5.1" />
    </system.web>

    <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
            <dependentAssembly>
                <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="0.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="System.Web.Http.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="0.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="0.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
            </dependentAssembly>
        </assemblyBinding>
    </runtime>
<system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>
</configuration>

任何人都可以指出我做错了什么,或者更重要的是,我可以改变什么来让事情发挥作用而不会抛出异常？

Answer 1

你使用的是什么版本的Ninject.Web.WebApi库？它看起来像2个星期前改变了一些东西.在此更改之前(v3.2.3和更早版本),HttpConfiguration绑定存在于Ninject.Web.WebApi.OwinHost.OwinWebApiModule和中的2个不同模块中Ninject.Web.WebApi.WebApiModule.在此更改(新版本为3.2.4)之后,此绑定仅发生一次.

Answer 2

我有同样的错误,但出于不同的原因:由于某种原因,我已经安装了两个Ninject.Web.WebApi.WebHost和Ninject.Web.WebApi.OwinHost.

如果您查看OwinWebApiModule.cs和WebApiWebHostModule.cs的源代码,则两个Ninject模块都有绑定HttpConfiguration.

我删除了Ninject.Web.WebApi.WebHost,一切都很好.

Answer 3

转到Referances并搜索Ninject.web.WebApi.WebHost,然后删除它.它将开始工作.