如何在startup.cs的Configure方法中使用ConfigurationBinder

Question

asp.net mvc 6 beta5

我曾尝试使用config.json来激活\ disactive日志记录

public IConfiguration Configuration { get; set; }

public Startup(IHostingEnvironment env, IApplicationEnvironment appEnv)
         {
            var configurationBuilder = new ConfigurationBuilder(appEnv.ApplicationBasePath)
            .AddJsonFile("config.json")
            .AddEnvironmentVariables();
            Configuration = configurationBuilder.Build();

            DBContext.ConnectionString = Configuration.Get("Data:DefaultConnection:ConnectionString");
        }

public void ConfigureServices(IServiceCollection services)
        {
            services.AddOptions();
            services.Configure<AppSettings>(Configuration.GetConfigurationSection("AppSettings"));
        }

// Configure is called after ConfigureServices is called.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerfactory)
        {
            // that line cause NullReferenceException  
            AppSettings settings = ConfigurationBinder.Bind<AppSettings>(Configuration);  
             if (settings.Log.IsActive)
             {
              ................
        }

ASP.NET 5(vNext)中的示例- 获取配置设置 和http://perezgb.com/2015/07/04/aspnet-5-typed-settings-with-the-configurationbinder/
是否有其他方法可以获得"configure"方法中AppSettings的实例？我需要输入对象.

Answer 1

你可以使用服务定位器得到它:

IOptions<AppSettings> settings = app.ApplicationServices.GetService<IOptions<AppSettings>>();
if (settings.Options.whatever)
  {
     ...
  }

我注意到,如果您使用VS 2015的最终版本创建一个新项目,项目模板不包含AppSettings,就像之前的项目模板那样,不确定原因.

Answer 2

配置中的每个服务ConfigureServices都可以Configure由运行时注入到方法中：

public void Configure(IApplicationBuilder app, IOptions<AppSettings> options)
{
    // access options.Options here
}

这是一个比ServiceProvider直接访问更简洁的解决方案。