如何为同一具体类型注册带不同构造参数的命名服务？

.NET原生DI本身不支持你想要的.Name()命名服务方式，不过可以通过以下几种方案实现需求：

方案一：.NET 8+ 原生Keyed服务（推荐） #

从.NET 8开始，官方DI新增了Keyed服务功能，完美匹配你的场景，直接按名称标识同类型的不同实例：

注册代码 #

builder.Services.AddKeyedScoped<WeatherForecastService>("my_first_service_named", 
    sp => new WeatherForecastService("param1", "param2"));

builder.Services.AddKeyedScoped<WeatherForecastService>("my_second_service_named", 
    sp => new WeatherForecastService("param3", "param4"));

注入使用 #

通过[FromKeyedServices]特性指定要注入的服务key：

public class YourController
{
    private readonly WeatherForecastService _firstService;
    private readonly WeatherForecastService _secondService;

    public YourController(
        [FromKeyedServices("my_first_service_named")] WeatherForecastService first,
        [FromKeyedServices("my_second_service_named")] WeatherForecastService second)
    {
        _firstService = first;
        _secondService = second;
    }
}

方案二：创建标记派生类（兼容旧版本） #

如果你的项目基于.NET 8以下版本，可以给原服务类创建两个空的派生类，用类型作为区分标识：

定义标记类 #

// 仅作为标记，继承原服务类
public class FirstWeatherForecastService : WeatherForecastService
{
    public FirstWeatherForecastService(string p1, string p2) : base(p1, p2) { }
}

public class SecondWeatherForecastService : WeatherForecastService
{
    public SecondWeatherForecastService(string p1, string p2) : base(p1, p2) { }
}

注册与注入 #

// 注册
builder.Services.AddScoped<FirstWeatherForecastService>(sp => new FirstWeatherForecastService("param1", "param2"));
builder.Services.AddScoped<SecondWeatherForecastService>(sp => new SecondWeatherForecastService("param3", "param4"));

// 注入使用
public class YourController
{
    private readonly WeatherForecastService _firstService;
    private readonly WeatherForecastService _secondService;

    public YourController(FirstWeatherForecastService first, SecondWeatherForecastService second)
    {
        _firstService = first;
        _secondService = second;
    }
}

方案三：自定义服务工厂（灵活适配） #

如果需要更灵活的服务获取逻辑，可以创建工厂类统一管理不同实例：

定义工厂类 #

public class WeatherForecastServiceFactory
{
    public WeatherForecastService GetService(string serviceName)
    {
        return serviceName switch
        {
            "my_first_service_named" => new WeatherForecastService("param1", "param2"),
            "my_second_service_named" => new WeatherForecastService("param3", "param4"),
            _ => throw new ArgumentException($"未知服务名称：{serviceName}")
        };
    }
}

注册与使用 #

// 注册工厂
builder.Services.AddScoped<WeatherForecastServiceFactory>();

// 注入使用
public class YourController
{
    private readonly WeatherForecastService _firstService;
    private readonly WeatherForecastService _secondService;

    public YourController(WeatherForecastServiceFactory factory)
    {
        _firstService = factory.GetService("my_first_service_named");
        _secondService = factory.GetService("my_second_service_named");
    }
}

内容的提问来源于stack exchange，提问作者levis84