Question

我有一个ASP.Net Core应用程序，可在IIS Express下以开发人员模式运行。我已经发布到Windows 10 IIS网站，但是出现以下错误：

An error occurred while starting the application.
ArgumentNullException: Value cannot be null.
Parameter name: implementationInstance
Microsoft.Extensions.DependencyInjection.ServiceCollectionServiceExtensions.AddSingleton<TService>(IServiceCollection services, TService implementationInstance)

ArgumentNullException: Value cannot be null. Parameter name: implementationInstance
Microsoft.Extensions.DependencyInjection.ServiceCollectionServiceExtensions.AddSingleton<TService>(IServiceCollection services, TService implementationInstance)
NSG.WebSrv.Startup.ConfigureServices(IServiceCollection services) in Startup.cs
-
            // services.Configure<AuthSettings>(Configuration.GetSection("AuthSettings"));
            AuthSettings _authSettings = new AuthSettings();
            _authSettings = Options.Create<AuthSettings>(
                Configuration.GetSection("AuthSettings").Get<AuthSettings>()).Value;
            services.AddSingleton<AuthSettings>(_authSettings);
            //
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });
            // Add MediatR from MediatR.Extensions.Microsoft.DependencyInjection package
Microsoft.AspNetCore.Hosting.ConventionBasedStartup.ConfigureServices(IServiceCollection services)
Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices()
Microsoft.AspNetCore.Hosting.Internal.WebHost.Initialize()
Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

Show raw exception details
.NET Core 4.6.28207.03 X64 v4.0.0.0    |   Microsoft.AspNetCore.Hosting version 2.2.7-servicing-10089    |    Microsoft Windows 10.0.18362    |   Need help?

错误发生在以下行：

   services.Configure<CookiePolicyOptions>(options =>

使用无托管代码配置IIS站点App-Pool。

已部署/翻译的 web.config 如下：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <!-- For more info see https://go.microsoft.com/fwlink/?linkid=838655 -->
  <!--   -->
  <system.webServer>
    <handlers>
      <remove name="aspNetCore" />
      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
    </handlers>
    <!-- https://scottsauber.com/2017/04/10/how-to-troubleshoot-an-error-occurred-while-starting-the-application-in-asp-net-core-on-iis/  -->
    <aspNetCore processPath="dotnet" arguments=".\NSG.WebSrv.dll" stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" hostingModel="InProcess">
      <environmentVariables>
        <environmentVariable name="ASPNETCORE_ENVIRONMENT" value="Development" />
      </environmentVariables>
    </aspNetCore>
  </system.webServer>
  <!--   -->
</configuration>
<!--ProjectGuid: bcfdd09f-8928-4e80-a804-82728c9bbe16-->

如果我注释掉它出错的代码块，那么它将在下一行代码中出错。

启动的开始如下：

public class Startup
{
    //
    public Startup(IConfiguration configuration, ILoggerFactory loggerFactory)
    {
        Configuration = configuration;
        LoggerFactory = loggerFactory;
    }
    //
    /// <summary>
    /// IConfiguration, common configuration provider.
    /// </summary>
    public IConfiguration Configuration { get; }
    //
    /// <summary>
    /// The logger factory
    /// </summary>
    public static ILoggerFactory LoggerFactory = null;
    //
    /// <summary>
    /// The configured logger (console).
    /// </summary>
    public static ILogger<ConsoleLoggerProvider> AppLogger = null;
    //
    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        //
        services.Configure<IISServerOptions>(options =>
        {
            // do not use windows authentication
            options.AutomaticAuthentication = false;
        });
        // Configure logging
        // Unable to resolve service for type 'Microsoft.Extensions.Logging.ILogger' while attempting to activate 'NSG.WebSrv.Infrastructure.Notification.NotificationService'
        services.AddLogging(builder => builder
            .AddConfiguration(Configuration.GetSection("Logging"))
            .AddConsole()
            .AddDebug()
        );
        AppLogger = LoggerFactory.CreateLogger<ConsoleLoggerProvider>();
        services.TryAdd(ServiceDescriptor.Singleton<ILoggerFactory, LoggerFactory>());
        services.TryAdd(ServiceDescriptor.Singleton(typeof(ILogger<>), typeof(Logger<>)));
        // Add and configure email/notification services
        services.Configure<MimeKit.NSG.EmailSettings>(Configuration.GetSection("EmailSettings"));
        services.Configure<ServicesSettings>(Configuration.GetSection("ServicesSettings"));
        services.Configure<ApplicationSettings>(Configuration.GetSection("ApplicationSettings"));
        // services.Configure<AuthSettings>(Configuration.GetSection("AuthSettings"));
        AuthSettings _authSettings = new AuthSettings();
        _authSettings = Options.Create<AuthSettings>(
            Configuration.GetSection("AuthSettings").Get<AuthSettings>()).Value;
        services.AddSingleton<AuthSettings>(_authSettings);
        //
        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });
        ...
    }
    ...
}

完整的解决方案在GitHub上。

Answer 1

您是否已为IIS安装了.NetCore HostingBundle？

Answer 2

我创建了一个新的解决方案并将其发布，并且模板可以正常工作。然后，我添加了我的 Program.cs 和一些我的 Startup.cs 文件，但失败了。它在 _authSettings 上失败，因为我没有安装正确的 appsettings.json ，但它基本上指出了以前的任何失败都可能导致此问题的事实。然后，当我对日志一无所知时，我发现了一段很早就添加的代码，删除该行，现在可以了：

services.TryAdd(ServiceDescriptor.Singleton(typeof(ILogger<>), typeof(Logger<>)));

这在 IISExpress 下没有失败，但是在 w3wp 下确实引起了问题。

注意：这是我的第一个.Net Core Web应用程序。

发布到IIS ASP.Net Core导致“值不能为空”错误

2 个答案: