通过 DI 在运行时注册服务? [英] Register Service at Runtime via DI?

问题描述

我正在使用 ASP.NET Core，并希望在运行时向 IServiceProvider 添加一个服务，以便它可以通过 DI 在整个应用程序中使用.

I am using ASP.NET Core and want to add a service to the IServiceProvider at runtime, so it can be used across the application via DI.

例如，一个简单的例子是用户转到设置控制器并将身份验证设置从开"更改为关".在这种情况下，我想替换在运行时注册的服务.

For instance, a simple example would be that the user goes to the settings controller and changes an authentication setting from "On" to "Off". In that instance I would like to replace the service that was registered at runtime.

设置控制器中的伪代码:

Psuedo Code in the Settings Controller:

if(settings.Authentication == false)
{
     services.Remove(ServiceDescriptor.Transient<IAuthenticationService, AuthenticationService>());
     services.Add(ServiceDescriptor.Transient<IAuthenticationService, NoAuthService>());
}
else
{
     services.Remove(ServiceDescriptor.Transient<IAuthenticationService, NoAuthService>
     services.Add(ServiceDescriptor.Transient<IAuthenticationService, AuthenticationService>());
}

当我在 Startup.cs 中执行此逻辑时，此逻辑工作正常，因为 IServiceCollection 尚未内置到 IServiceProvider 中.但是，我希望能够在启动已经执行后执行此操作.有谁知道这是否可能?

This logic works fine when I am doing it in my Startup.cs because the IServiceCollection has not been built into a IServiceProvider. However, I want to be able to do this after the Startup has already executed. Does anyone know if this is even possible?

推荐答案

不是在运行时注册/删除服务，我会创建一个服务工厂，在运行时决定正确的服务.

Instead of registering/removing service at runtime, i would create a service factory which decides right service at runtime.

services.AddTransient<AuthenticationService>();
services.AddTransient<NoAuthService>();
services.AddTransient<IAuthenticationServiceFactory, AuthenticationServiceFactory>();

AuthenticationServiceFactory.cs

AuthenticationServiceFactory.cs

public class AuthenticationServiceFactory: IAuthenticationServiceFactory
{
     private readonly AuthenticationService _authenticationService;
     private readonly NoAuthService_noAuthService;
     public AuthenticationServiceFactory(AuthenticationService authenticationService, NoAuthService noAuthService)
     {
         _noAuthService = noAuthService;
         _authenticationService = authenticationService;
     }
     public IAuthenticationService GetAuthenticationService()
     {
          if(settings.Authentication == false)
          {
             return _noAuthService;
          }
          else
          {
              return _authenticationService;
          }
     }
}

在课堂上的使用:

public class SomeClass
{
    public SomeClass(IAuthenticationServiceFactory _authenticationServiceFactory)
    {
        var authenticationService = _authenticationServiceFactory.GetAuthenticationService();
    }
}

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