c# - 没有注册类型 'IServiceProviderFactory[Autofac.ContainerBuilder]' 的服务

Question

运行以下命令添加数据库迁移脚本时，出现以下错误:

dotnet ef migrations add InitialCreate -v -o .\Migrations\ --context MyContext

An error occurred while accessing the Microsoft.Extensions.Hosting services. Continuing without the application service provider. Error: No service for type 'Microsoft.Extensions.DependencyInjection.IServiceProviderFactory`1[Autofac.ContainerBuilder]' has been registered.

我关注了this文档。 Startup 类的实现如下:

public class Startup
{
    public Startup(IConfiguration configuration, IHostingEnvironment env)
    {
        Configuration = configuration;
        WebHostingEnvironment = env;
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddEnvironmentVariables();
        this.Configuration = builder.Build();
    }

    public void ConfigureServices(IServiceCollection services)
    {
        services
            .AddMvc(options => options.EnableEndpointRouting = false)
            .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);

        services.AddCustomDbContext(Configuration);
        services.AddOptions();
    }

    public void ConfigureContainer(ContainerBuilder builder)
    { }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseDeveloperExceptionPage();
        app.UseHttpsRedirection();
        app.UseMvc();
        ConfigureEventBus(app);
    }
}

对导致错误的原因以及如何修复它有任何想法吗？

版本:

<TargetFramework>netcoreapp3.1</TargetFramework>
<PackageReference Include="Autofac" Version="4.9.4" />
<PackageReference Include="Autofac.Extensions.DependencyInjection" Version="5.0.1" />

Answer 1

你必须在 Program.cs 中配置 Autofac:

var hostBuilder = new WebHostBuilder()
            .UseContentRoot(Path.GetDirectoryName(path))
            .ConfigureServices(services => services.AddAutofac())
            .ConfigureAppConfiguration(cb =>
            {
                cb.AddJsonFile("appsettings.json", optional: false).AddEnvironmentVariables();
            }).UseStartup<Startup>();

或

 return Host.CreateDefaultBuilder(args)
            .UseServiceProviderFactory(new AutofacServiceProviderFactory())
            .ConfigureAppConfiguration((builderContext, config) =>
            {
                config.AddJsonFile("appsettings.json", optional: true);
            })
            .ConfigureWebHostDefaults(webBuilder =>
            {   
                webBuilder.UseStartup<Startup>();
            });