c# - 启动后向 IServiceCollection 注册类

Question

在我的应用程序中，我有一堆要在启动后注册的服务。

晚课：

public LateClass(IServiceCollection col)
{
    col.AddTransient<IEventHandler, JsonPackageUpdated>();
}

当然还要注册 LateClass 本身：

 public void ConfigureServices(IServiceCollection services)
 {
     col.AddTransient<LateClass>();
 }

但是 IServiceCollection 会破坏我的应用程序，并且我遇到了一个我无法解决的异常。

标签： c#.net-coredependency-injection

Answer 1

在评论中回答 OP 的问题应该如何处理动态配置。

您可以根据需要使您的 ConfigurationService 尽可能多的复杂性（注入其他注入了其他内容的服务），直到它具有循环依赖关系。

using Microsoft.Extensions.DependencyInjection;
using System;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var collection = new ServiceCollection();

            collection.AddTransient<ConfigurationService>();
            collection.AddTransient<EventProcessService>();


            var serviceProvider = collection.BuildServiceProvider();

            var eventService = serviceProvider.GetService<EventProcessService>();

            eventService.ProcessEvent(0);
        }
    }

    public class ConfigurationService
    {
        public ConfigurationService(
                // you could use whatever configuration provider you have: db context for example
            )
        {
        }

        public string GetSettingBasedOnEventType(int eventType)
        {
            switch (eventType)
            {
                case 0:
                    return "Some setting value";
                case 1:
                    return "Some other setting value";
                default:
                    return "Not found";
            }
        }
    }

    public class EventProcessService
    {
        private readonly ConfigurationService configurationService;

        public EventProcessService(ConfigurationService configurationService)
        {
            this.configurationService = configurationService;
        }

        public void ProcessEvent(int eventType)
        {
            var settingForEvent = configurationService.GetSettingBasedOnEventType(eventType);

            // process event with your setting
        }
    }
}