public class Startup

    {

        public Startup(IHostingEnvironment env)

        {

            Configuration = new ConfigurationBuilder()

                .SetBasePath(env.ContentRootPath)

                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)

                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)

                .AddEnvironmentVariables()

                .Build();

        }

        public IConfiguration Configuration { get; }

Configuration.GetSection("AppConfig")["DbConn"]