c# - “不支持返回 System.IServiceProvider 的 ConfigureServices。”

Question

我需要在 ASP core 3.0 中使用这个 AutoFac

当我在启动时使用这段代码:

public IServiceProvider ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    return services.BuildAutofacServiceProvider();
}

它告诉我这个错误:

'ConfigureServices returning an System.IServiceProvider isn't supported.'

然后我将 program.cs 更改为:

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
        .UseServiceProviderFactory(new AutofacServiceProviderFactory())
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

但是没有解决。

这是 BuildAutofacServiceProvider() 代码:

public static IServiceProvider BuildAutofacServiceProvider(this IServiceCollection services)
{
    var ContainerBuilder = new ContainerBuilder();
    ContainerBuilder.Populate(services);
    ContainerBuilder.AddService();
    var container = ContainerBuilder.Build();

    return new AutofacServiceProvider(container);
}

我该如何解决这个问题？

Answer 1

为 ASP.NET Core 3.0+ 配置 Autofac 的启动语法已更改

除了在host builder上使用以下内容

.UseServiceProviderFactory(new AutofacServiceProviderFactory())

在Startup中执行以下格式

public void ConfigureServices(IServiceCollection services) {
    //... normal registration here

    // Add services to the collection. Don't build or return
    // any IServiceProvider or the ConfigureContainer method
    // won't get called.

    services.AddControllers();
}

// ConfigureContainer is where you can register things directly
// with Autofac. This runs after ConfigureServices so the things
// here will override registrations made in ConfigureServices.
// Don't build the container; that gets done for you. If you
// need a reference to the container, you need to use the
// "Without ConfigureContainer" mechanism shown later.
public void ConfigureContainer(ContainerBuilder builder) {
    // Register your own things directly with Autofac
    builder.AddMyCustomService();

    //...
}

引用 Autofac documentation适用于 ASP.NET Core 3.0+