ASP.NET Core MVC创建并关联JSON配置文件

1.目录下创建 appsettings.json文件

内容：

{
    "ConnectionStrings": {
        "DefaultConnection": "Databases = InMemory;",
        "Myname": "Lihuahua;"
    }
}

2.创建Settings文件夹下，新增类

类具体内容：(属性的名字和appsettings.json文件中键值对的键相对应)

namespace TestMvc.Settings
{
    public class ConnectionStringOptions
    {
        public string DefaultConnection { get; set; }
        public string Myname { get; set; }
    }
}

3.在Startup方法中注册服务

        //Startup中添加    
        //构造方法
        private readonly IConfiguration _configuration;
        public Startup(IConfiguration configuration)
        {
            _configuration = configuration;
        }

ConfigureServices方法中关联服务

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();//使用该方法后才可以使用app.UseMvc()方法
            services.AddSingleton<Ifactory, Factory>();
            //关联起来
            services.Configure<ConnectionStringOptions>(_configuration.GetSection("ConnectionStrings"));
        }

4.引用
csHtml中引用

@using Microsoft.Extensions.Options;
@inject IOptions<TestMvc.Settings.ConnectionStringOptions> ioption;
<div class="jumbotron">
    <h1 class="display-4"> @ioption.Value.Myname</h1>
</div>

后台引用

    public class HomeController:Controller 
    {
        //构造方法中初始化值
        private IOptions<ConnectionStringOptions> option;
        public HomeController(IOptions<ConnectionStringOptions> options)
        {
            this.option = options;
        }
     }

PS：

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration((context,builder)=> { 
            builder.//这里选择添加配置文件的格式
            })
                .UseStartup<Startup>();