【发布时间】：2016-11-25 04:05:09
【问题描述】：
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 依赖注入，并最终托管在 IIS 中。我已按照文章“与 ASP.NET Web.API2、OWIN 和 Ninject 交朋友”中的说明进行操作：http://www.alexzaitzev.pro/2014/11/webapi2-owin-and-ninject.html，但我使用了一个空的 Web 应用程序项目，并且没有勾选“包括 Web API 引用和文件夹” " 创建项目时。
当我启动新 API 并发出页面请求时，我收到以下 Ninject.ActivationException 抛出：
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.
刷新浏览器后，此异常消失。我真的不明白是什么导致了这个异常。从我的角度来看，在 OWIN 上下文和 Ninject 中对 WebAPI 有点缺乏经验，很难知道问题出在哪里。是与Ninject...吗？是在 OWIN 中吗...？是在 WebAPI 中吗...？
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>
谁能指出我做错了什么，或者更重要的是，我可以改变什么来让事情正常工作而不会引发异常？
【问题讨论】：
标签： asp.net-web-api ninject owin