.NET Core中使用字符串（配置文件）的ServiceCollection配置

本文介绍了.NET Core中使用字符串（配置文件）的ServiceCollection配置的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

是否可以在核心中的标准 Microsoft.Extensions.DependencyInjection.ServiceCollection 库中配置依赖项注入，而实际上没有引用题？ （要从配置文件中获取实现类名称？）

Is there a way to configure dependency injection in the standard Microsoft.Extensions.DependencyInjection.ServiceCollection library in core, without actually having a reference to the implementation classes in question? (to get implementation class names from configuration files?)

例如：

services.AddTransient<ISomething>("The.Actual.Thing");// Where The.Actual.Thing is a concrete class

推荐答案

如果您真的想使用字符串参数动态加载对象，则可以使用创建动态对象的工厂。

If your really keen to use strings parameters to load objects on the fly, you can use a factory that creates dynamic objects.

public interface IDynamicTypeFactory { object New(string t); } public class DynamicTypeFactory : IDynamicTypeFactory { object IDynamicTypeFactory.New(string t) { var asm = Assembly.GetEntryAssembly(); var type = asm.GetType(t); return Activator.CreateInstance(type); } }

假设您提供以下服务

public interface IClass { string Test(); } public class Class1 : IClass { public string Test() { return "TEST"; } }

您可以

public void ConfigureServices(IServiceCollection services) { services.AddTransient<IDynamicTypeFactory, DynamicTypeFactory>(); } // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IDynamicTypeFactory dynamicTypeFactory) { loggerFactory.AddConsole(); if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app.Run(async (context) => { var t = (IClass)dynamicTypeFactory.New("WebApplication1.Class1"); await context.Response.WriteAsync(t.Test()); }); }