ASP.NET Core 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 run 时不会抛出错误

Question

在 IIS Express 上从 Visual Studio 2019 运行我的应用程序时，网页给出错误 500.30 并在输出中显示，

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

但是，在使用dotnet watch run该页面的终端中运行它时，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();

在我下面的 ConfigureServes 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();
        }

我还尝试修复我的 Visual Studio 2019 以及重新安装 .NET 3.1.100 SDK，但没有成功。

任何帮助将不胜感激！

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

我在 IISExpress 上遇到了同样的问题。我能摆脱 500.30 错误的唯一方法是在 OutOfProcess 模式下运行应用程序。

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

Answer 2

github上有一个关于这个问题的问题。

*不支持在 ASP.NET Core 3.0/3.1 项目中使用 2.x 版本的 Microsoft.Extensions.* 和 Microsoft.AspNetCore.* 包。

就我而言，我依赖于 nuget 包，该包依赖于 Microsoft.AspNetCore 2.xx 删除 nuget 后，项目在 IIS Express 下运行没有问题。

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。