public class FileLogger
{
    public void LogInfo(string message)
    {

    }
}

public class MyService
{
    private readonly FileLogger _logger = new FileLogger();

    public void Get()
    {
        _logger.LogInfo("MyService.Get");
    }
}

public class MyService
{
    private readonly ElkLogger _logger = new ElkLogger();

    public void Get()
    {
        _logger.LogInfo("MyService.Get");
    }
}

public class Service1 : IDisposable
{
    public void Dispose()
    {
        Console.WriteLine("Service1.Dispose");
    }
}

public class Service2 : IDisposable
{
    public void Dispose()
    {
        Console.WriteLine("Service2.Dispose");
    }
}

public class Service3 : IDisposable
{
    public void Dispose()
    {
        Console.WriteLine("Service3.Dispose");
    }
}

public class Service4 : IDisposable
{
    public void Dispose()
    {
        Console.WriteLine("Service4.Dispose");
    }
}

public void ConfigureServices(IServiceCollection services)
{
    // 每次使用完（請(qǐng)求結(jié)束時(shí)）即釋放
    services.AddTransient<Service1>();
    // 超出范圍（請(qǐng)求結(jié)束時(shí)）則釋放
    services.AddScoped<Service2>();
    // 程序停止時(shí)釋放
    services.AddSingleton<Service3>();
    // 程序停止時(shí)釋放
    services.AddSingleton(sp => new Service4());
}

public ValuesController(
    Service1 service1, 
    Service2 service2, 
    Service3 service3, 
    Service4 service4)
{ }

public void ConfigureServices(IServiceCollection services)
{
    // 注意與上面的區(qū)別，這個(gè)是直接 new 的，而上面是通過(guò) sp => new 的
    services.AddSingleton(new Service1());
    services.AddSingleton(new Service2());
    services.AddSingleton(new Service3());
    services.AddSingleton(new Service4());
}

services.AddSingleton<IMyService, MyService>();
services.AddSingleton<IMyService, MyService>();

services.AddTransient<IMyService, MyService1>();
// 由于上面已經(jīng)注冊(cè)了服務(wù)類型 IMyService，所以下面的代碼不不會(huì)執(zhí)行任何操作（與生命周期無(wú)關(guān)）
services.TryAddTransient<IMyService, MyService1>();
services.TryAddTransient<IMyService, MyService2>();

// 注冊(cè)了 IMyService - MyService1
services.TryAddEnumerable(ServiceDescriptor.Singleton<IMyService, MyService1>());
// 注冊(cè)了 IMyService - MyService2
services.TryAddEnumerable(ServiceDescriptor.Singleton<IMyService, MyService2>());
// 未進(jìn)行任何操作，因?yàn)?IMyService - MyService1 在上面已經(jīng)注冊(cè)了
services.TryAddEnumerable(ServiceDescriptor.Singleton<IMyService, MyService1>());

public interface IAnimalService { }
public class DogService : IAnimalService { }
public class PigService : IAnimalService { }
public class CatService : IAnimalService { }

public void ConfigureServices(IServiceCollection services)
{
    // 生命周期沒(méi)有限制
    services.AddTransient<IAnimalService, DogService>();
    services.AddScoped<IAnimalService, PigService>();
    services.AddSingleton<IAnimalService, CatService>();
}

public ValuesController(
    // CatService
    IAnimalService animalService,   
    // DogService、PigService、CatService
    IEnumerable<IAnimalService> animalServices)
{
}

// 將 IMyService 的實(shí)現(xiàn)替換為 MyService1
services.Replace(ServiceDescriptor.Singleton<IMyService, MyService>());
// 移除 IMyService 注冊(cè)的實(shí)現(xiàn) MyService
services.Remove(ServiceDescriptor.Singleton<IMyService, MyService>());
// 移除 IMyService 的所有注冊(cè)
services.RemoveAll<IMyService>();
// 清除所有服務(wù)注冊(cè)
services.Clear();

Install-Package Autofac
Install-Package Autofac.Extensions.DependencyInjection

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        // 通過(guò)此處將默認(rèn)服務(wù)提供器工廠替換為 autofac
        .UseServiceProviderFactory(new AutofacServiceProviderFactory());

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public ILifetimeScope AutofacContainer { get; private set; }

    public void ConfigureServices(IServiceCollection services)
    {
        // 1. 不要 build 或返回任何 IServiceProvider，否則會(huì)導(dǎo)致 ConfigureContainer 方法不被調(diào)用。
        // 2. 不要?jiǎng)?chuàng)建 ContainerBuilder，也不要調(diào)用 builder.Populate()，AutofacServiceProviderFactory 已經(jīng)做了這些工作了
        // 3. 你仍然可以在此處通過(guò)微軟默認(rèn)的方式進(jìn)行服務(wù)注冊(cè)
        
        services.AddOptions();
        services.AddControllers();
        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v1", new OpenApiInfo { Title = "WebApplication.Ex", Version = "v1" });
        });
    }

    // 1. ConfigureContainer 用于使用 Autofac 進(jìn)行服務(wù)注冊(cè)
    // 2. 該方法在 ConfigureServices 之后運(yùn)行，所以這里的注冊(cè)會(huì)覆蓋之前的注冊(cè)
    // 3. 不要 build 容器，不要調(diào)用 builder.Populate()，AutofacServiceProviderFactory 已經(jīng)做了這些工作了
    public void ConfigureContainer(ContainerBuilder builder)
    {
        // 將服務(wù)注冊(cè)劃分為模塊，進(jìn)行注冊(cè)
        builder.RegisterModule(new AutofacModule());
    }
    
    public class AutofacModule : Autofac.Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            // 在此處進(jìn)行服務(wù)注冊(cè)
            builder.RegisterType<UserService>().As<IUserService>();
        }
    }

    public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
    {
        // 通過(guò)此方法獲取 autofac 的 DI容器
        AutofacContainer = app.ApplicationServices.GetAutofacRoot();
    }
}

[HttpGet]
public string Get([FromServices]IMyService myService)
{
    return "Ok";
}

public interface IUserService 
{
    string Get();
}

public class UserService : IUserService
{
    public string Get()
    {
        return "User";
    }
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers().AddControllersAsServices();
}

public void ConfigureContainer(ContainerBuilder builder)
{
    builder.RegisterModule<AutofacModule>();
}

public class AutofacModule : Autofac.Module
{
    protected override void Load(ContainerBuilder builder)
    {
        builder.RegisterType<UserService>().As<IUserService>();

        var controllerTypes = Assembly.GetExecutingAssembly().GetExportedTypes()
            .Where(type => typeof(ControllerBase).IsAssignableFrom(type))
            .ToArray();

        // 配置所有控制器均支持屬性注入
        builder.RegisterTypes(controllerTypes).PropertiesAutowired();
    }
}

public class ValuesController : ControllerBase
{
    public IUserService UserService { get; set; }

    [HttpGet]
    public string Get()
    {
        return UserService.Get();
    }
}

using Microsoft.Extensions.DependencyInjection;

public class ValuesController : ControllerBase
{
    private readonly IServiceProvider _serviceProvider;

    // 應(yīng)通過(guò)依賴注入的方式獲取服務(wù)實(shí)例
    public ValuesController(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    [HttpGet]
    public string Get()
    {
        // 盡量避免通過(guò) GetService 方法獲取服務(wù)實(shí)例
        var myService = _serviceProvider.GetService<IMyService>();

        return "Ok";
    }
}

public void ConfigureServices(IServiceCollection services)
{
    // 不要在該方法中調(diào)用該方法
    var serviceProvider = services.BuildServiceProvider();
}

namespace Microsoft.Extensions.DependencyInjection
{
    public static class ApplicationServiceCollectionExtensions
    {
        public static IServiceCollection AddApplicationService(this IServiceCollection services)
        {
            services.AddTransient<Service1>();
            services.AddScoped<Service2>();
            services.AddSingleton<Service3>();
            services.AddSingleton(sp => new Service4());

            return services;
        }
    }
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddApplicationService();
}