KeyNotFoundException in Startup ConfigureServices AddMvc()

Question

自30.05.2018以来，我的ASP.NET核心代码在Startup.cs中

public IServiceProvider ConfigureServices(IServiceCollection services)
{
   // Add services to the collection.
   services.AddMvc();
}

按以下方式抛出异常：

启动应用程序时出错。KeyNotFoundException:给定的密钥在字典中不存在。

KeyNotFoundException:给定的密钥在字典中不存在。( System.Collections.Generic.Dictionary.get_Item(TKey键) Microsoft.AspNetCore.Mvc.Internal.DefaultAssemblyPartDiscoveryProvider+CandidateResolver.ComputeClassification(string依赖) Microsoft.AspNetCore.Mvc.Internal.DefaultAssemblyPartDiscoveryProvider+CandidateResolver.ComputeClassification(string依赖) Microsoft.AspNetCore.Mvc.Internal.DefaultAssemblyPartDiscoveryProvider+CandidateResolver.ComputeClassification(string依赖) Microsoft.AspNetCore.Mvc.Internal.DefaultAssemblyPartDiscoveryProvider+CandidateResolver.ComputeClassification(string依赖) Microsoft.AspNetCore.Mvc.Internal.DefaultAssemblyPartDiscoveryProvider+CandidateResolver+d__4.MoveNext() System.Linq.Enumerable+d__17.MoveNext() System.Linq.Enumerable+WhereSelectEnumerableIterator.( Microsoft.Extensions.DependencyInjection.MvcCoreServiceCollectionExtensions.GetApplicationPartManager(IServiceCollection服务) Microsoft.Extensions.DependencyInjection.MvcCoreServiceCollectionExtensions.AddMvcCore(IServiceCollection服务( Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddMvc(IServiceCollection服务) MyWebApiProject.Startup.ConfigureServices(IServiceCollection服务)( Startup.cs System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() Microsoft.AspNetCore.Hosting.ConventionBasedStartup.ConfigureServices(IServiceCollection服务) Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices() Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

csproj

<TargetFramework>net461</TargetFramework>

<ItemGroup>
<PackageReference Include="Autofac" Version="4.6.2" />
<PackageReference Include="Autofac.Extensions.DependencyInjection" Version="4.1.0" />
<PackageReference Include="EntityFramework" Version="6.2.0" />
<PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.1" />
<PackageReference Include="Microsoft.AspNetCore" Version="1.1.2" />
<PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="1.1.2" />
<PackageReference Include="Microsoft.AspNetCore.Mvc" Version="1.1.3" />
<PackageReference Include="Microsoft.AspNetCore.SignalR.Server" Version="0.2.0-preview2-22683" />
<PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="1.0.2" />
<PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.2" />
<PackageReference Include="Microsoft.IdentityModel.Tokens" Version="5.1.5" />
<PackageReference Include="Microsoft.VisualStudio.SlowCheetah" Version="3.0.61" />
<PackageReference Include="NLog.Web.AspNetCore" Version="4.4.1" />
<PackageReference Include="Swashbuckle.AspNetCore" Version="1.0.0" />
<PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="5.1.5" />
<PackageReference Include="System.Net.Http" Version="4.3.3" />

​

Answer 1

我也遇到了同样的问题。纠正这一问题的选项在这里概述，https://github.com/aspnet/Home/issues/3132

对我来说，我选择了在添加MVC之前添加ApplicationPartManager的选项，例如。

var manager = new ApplicationPartManager();
manager.ApplicationParts.Add(new AssemblyPart(typeof(Startup).Assembly));

services.AddSingleton(manager);
services.AddMvc();

来源

Answer 2

从几天前开始，我们也面临着同样的问题。

我们还注意到，我们和您都在使用AspNetCore 1.1 (一个相当旧的版本)。

凭直觉，我们更新了最新的(2.1)，这解决了我们的问题。

Answer 3

我们也面临着同样的问题。这就是我们将问题隔离到以下几个方面的程度: 1.重建旧版本的代码会导致构建工件中的XXXXX.deps.json发生更改。

 "compilationOptions": {
"defines": [
  "TRACE",
  "DEBUG",
  "NET461"
],

成了

"compilationOptions": {
"defines": [
  "TRACE",
  "DEBUG",
  "NETFRAMEWORK",
  "NET461"
],

和

      "HealthBizModel/1.0.0": {
    "runtime": {
      "HealthBizModel.dll": {}
    }
  },
  "HealthBizService/1.0.0": {
    "dependencies": {
      "HealthBizModel": "1.0.0"
    },

变成(依赖项是破坏它的部分)

  "HealthBizModel/1.0.0": {
    "dependencies": {
      "System.Runtime.Reference1": "4.0.20.0",
      "System.Net.Primitives.Reference1": "4.0.10.0",
      "System.Net.Http.WebRequest": "4.0.0.0"
    },
    "runtime": {
      "HealthBizModel.dll": {}
    }
  },
  "HealthBizService/1.0.0": {
    "dependencies": {
      "HealthBizModel": "1.0.0",
      "System.Text.Encoding.Reference1": "4.0.10.0"
    },

有趣的是，我们发现如果我们回滚第二段，删除依赖项，web应用程序就会启动并运行完全正常。所以如果你有紧急情况

进一步的解决尝试：-清除受影响项目中未使用的依赖项(为1构建工作，但奇怪的是再次开始失败)--向代理池中添加了一个新的VS2017构建代理，并使用该代理池构建:也没有改变。

我们还将尝试更多的想法，比如@Scott升级到DotNetCore2.0。

干杯,

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