不知道我在這里缺少什么，但是我無(wú)法從.net核心應(yīng)用程序中的appsettings.json獲取值。我有我的appsettings.json為：{    "AppSettings": {        "Version": "One"    }}啟動(dòng)：public class Startup{    private IConfigurationRoot _configuration;    public Startup(IHostingEnvironment env)    {        _configuration = new ConfigurationBuilder()    }    public void ConfigureServices(IServiceCollection services)    {      //Here I setup to read appsettings              services.Configure<AppSettings>(_configuration.GetSection("AppSettings"));    }}模型：public class AppSettings{    public string Version{ get; set; }}控制器：public class HomeController : Controller{    private readonly AppSettings _mySettings;    public HomeController(IOptions<AppSettings> settings)    {        //This is always null        _mySettings = settings.Value;    }}_mySettings始終為null。我在這里缺少什么嗎？