ASP.NET 核心 3.1 Web 应用程序在 IIS Express 上运行时抛出错误 500.30，但在使用 dotnet watch 运行时不会

Question

当运行在 IIS Express 上从 Visual Studio 2019 开始我的应用程序时，网页出现错误 500.30，并在输出中显示，

Exception thrown: 'System.NullReferenceException' in System.Private.CoreLib.dll

然而，当运行在终端中使用 dotnet watch run 将其连接时，页面运行没有错误并正确显示。

我试过运行调试器，错误总是在这一行抛出，

CreateHostBuilder(args).Build().Run();

在下面的 ConfigureSerives 方法完成后

// This method gets called by the runtime. Use this method to add services to the container.
        public static void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddRouting();
        }

我也试过修复我的 Visual Studio 2019 以及重新安装 .NET 3.1.100 SDK，但没有成功。

如有任何帮助，我们将不胜感激！

编辑：

我必须发布程序，然后运行 .exe，但这是我得到的输出

crit: Microsoft.AspNetCore.Hosting.Diagnostics[6]
      Application startup exception
System.IO.DirectoryNotFoundException: C:\Users\ray.kochenderfer\Documents\public\hub\public\
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root, ExclusionFilters filters)
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root)
   at QualityHub.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env) in C:\Users\ray.kochenderfer\repos\quality_hub\Startup.cs:line 49
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder)
   at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.<Build>b__0(IApplicationBuilder builder)
   at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass13_0.<UseStartup>b__2(IApplicationBuilder app)
   at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.<Configure>g__MiddlewareFilterBuilder|0(IApplicationBuilder builder)
   at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.<Configure>b__0(IApplicationBuilder app)
   at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken)
Unhandled exception. System.IO.DirectoryNotFoundException: C:\Users\ray.kochenderfer\Documents\public\hub\public\
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root, ExclusionFilters filters)
   at Microsoft.Extensions.FileProviders.PhysicalFileProvider..ctor(String root)
   at QualityHub.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env) in C:\Users\ray.kochenderfer\repos\quality_hub\Startup.cs:line 49
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder)
   at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.<Build>b__0(IApplicationBuilder builder)
   at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass13_0.<UseStartup>b__2(IApplicationBuilder app)
   at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.<Configure>g__MiddlewareFilterBuilder|0(IApplicationBuilder builder)
   at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.<Configure>b__0(IApplicationBuilder app)
   at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken)
   at Microsoft.Extensions.Hosting.Internal.Host.StartAsync(CancellationToken cancellationToken)
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token)
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token)
   at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host)
   at QualityHub.Program.Main(String[] args) in C:\Users\ray.kochenderfer\repos\quality_hub\Program.cs:line 16

Answer 1

这可能是由于多种原因造成的，如果没有日志记录，将很难确定发生了什么。

添加一个具有类似配置的web.config。 stdoutLogEnabled 将生成有助于进一步解决问题的日志，尤其是当它特定于 IIS Express 时。

<configuration>
  <location path="." inheritInChildApplications="false">
    <system.webServer>
      <handlers>
        <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
      </handlers>
      <aspNetCore processPath="dotnet"
                  arguments=".\MyApp.dll"
                  stdoutLogEnabled="false"
                  stdoutLogFile=".\logs\stdout"
                  hostingModel="inprocess" />
    </system.webServer>
  </location>
</configuration>

https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/aspnet-core-module?view=aspnetcore-3.1

Answer 2

我解决了这个问题。该问题与 ASP.NET 核心版本 2.2.0 与 Visual Studio 2019 版本 16.4.1 交互有关。我将 ASP.NET Core 降级到 2.1.7 版，然后将其更新回 2.2.0 版。这似乎解决了问题。

编辑：这只是暂时解决了这个问题。但是，降级到 2.1.7 似乎工作可靠。

Answer 3

关于这个问题有github issue。

Using 2.x versions of Microsoft.Extensions.* and Microsoft.AspNetCore.* packages in an ASP.NET Core 3.0/3.1 project is *not supported.

在我的例子中，我依赖于 nuget 包，它依赖于 Microsoft.AspNetCore 2.x.x。删除 nuget 后，项目运行在 IIS Express 下没有问题。

如果有人仍然遇到此问题，您可以尝试删除版本 2.x 的依赖项，因为它们会自动从 SDK 中解决。

Answer 4

我在使用 IISExpress 时遇到了同样的问题。我可以摆脱 500.30 错误的唯一方法是运行应用程序处于 OutOfProcess 模式。

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AspNetCoreHostingModel>OutOfProcess</AspNetCoreHostingModel>
  </PropertyGroup>

ASP.NET 核心 3.1 Web 应用程序在 IIS Express 上运行时抛出错误 500.30，但在使用 dotnet watch 运行时不会

ASP.NET Core 3.1 web application throws error 500.30 when run on IIS Express, but not when using dotnet watch run

c#

asp.net-core

iis-express

ASP.NET 核心 3.1 Web 应用程序在 IIS Express 上 运行 时抛出错误 500.30，但在使用 dotnet watch 运行 时不会

ASP.NET Core 3.1 web application throws error 500.30 when run on IIS Express, but not when using dotnet watch run

c#

asp.net-core

iis-express

ASP.NET 核心 3.1 Web 应用程序在 IIS Express 上运行时抛出错误 500.30，但在使用 dotnet watch 运行时不会