c# - startup.cs的Configure方法中如何使用ConfigurationBinder

Question

asp.net mvc 6 beta5

我尝试使用 config.json 来激活\禁用日志记录

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)
             {
              ................
        }

示例来自 ASP.NET 5 (vNext) - Getting a Configuration Setting和 http://perezgb.com/2015/07/04/aspnet-5-typed-settings-with-the-configurationbinder/
还有另一种方法可以在“配置”方法中获取 AppSettings 的实例吗？我需要键入的对象。

Answer 1

在 ConfigureServices 中配置的每个服务都可以由运行时注入(inject)到 Configure 方法中:

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

与直接访问 ServiceProvider 相比，这是一种更简洁的解决方案。