如何使用泛型类型注册依赖注入?(.net 核心) [英] How to register dependency injection with generic types? (.net core)

问题描述

我在 appSettings.json 文件中有一个带有多个参数的 asp.net 核心 Web 应用程序.

I have an asp.net core web app with multiple parameters in appSettings.json file.

我不想让服务在构造函数中包含 IOptions.

I didnt' want to have services having IOptions<MyObject> in the constructor.

我想在构造函数中使用 MyObject.所以我找到了以下文章:https://weblog.west-wind.com/posts/2017/dec/12/easy-configuration-binding-in-aspnet-core-revisited 很有趣.

I wanted MyObject in the constructor. So I found the following article: https://weblog.west-wind.com/posts/2017/dec/12/easy-configuration-binding-in-aspnet-core-revisited which is very interesting.

但我想更进一步.我想创建一个扩展方法来生成注入.

But I want to go further. I would like to create an extension method to generate the injection.

这是我想要做的:

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Common.WebTools.Extensions
{
    public static class IServiceCollectionExtensions
    {
        public static IServiceCollection AddSingletonConfigurationObject<T>(this IServiceCollection services, 
            IConfiguration configuration,
            string appSettingsKey) where T:new()
        {   
            var obj2 = new T();
            configuration.Bind(appSettingsKey, obj);
            services.AddSingleton(obj2); //compilation failed
            return services;
        }
    }
}

然后在我的 ConfigureServices 方法中我可以调用

And then in my ConfigureServices method I can call

services.AddSingletonConfigurationObject<Common.Tools.Configuration.GoogleAnalyticsConfiguration>(Configuration, "GoogleAnalytics");

但是我在这一行有一个编译错误:

But I Have a compliation error on this line:

services.AddSingleton(obj2); 

有人知道我该如何纠正错误吗?

Does somebody know how could I correct the error?

推荐答案

您可以使用 services.AddScoped 在范围请求中仅使用 1 个实例.因此，与 AddTransient 相比，总体上有所改进

You can use services.AddScoped to use only 1 instance in the scope request. So in general improvement compare to AddTransient

services.AddScoped(typeof(IGenericRepository<>), typeof(GenericRepository<>));

所以我的界面和类看起来像这样

So my interface and class will look like this

public interface IGenericRepository<T> where T : class

public class GenericRepository<T> : IGenericRepository<T> where T : class

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