解決條件依賴關系autofac

Question

我試圖根據條件解決依賴關系。

private static readonly Dictionary<string, Action<ContainerBuilder>> QRTypeDictionary = 
    new Dictionary<string, System.Action<ContainerBuilder>> () {
            { "REST" , (builder)=> builder
                                    .RegisterType<RestPublisher>()
                                    .As<Publisher>()},
            { "DB" , (builder)=> builder
                                    .RegisterType<DBPublisher>()
                                    .As<Publisher>()}
 }

我只是想確定這是否是根據條件解決依賴關系的唯一方法。 到目前為止我一直在使用Ninject，我正在尋找以下內容：

kernel.Bind<Publisher>()
      .To<DbPublisher>()
      .When(x => Defs.AppSettings.PublisherType == "DB")

只是想確保我使用Autofac做正確的事情

Answer 1

我可以看到3個解決方案來實現你想要的。

1. 使用lambda

    builder.RegisterType<DbPublisher>().AsSelf(); builder.RegisterType<RestPublisher>().AsSelf(); builder.Register(c => { switch(Defs.AppSettings.PublisherType){ case "DB": c.Resolve<DbPublisher>(); break; case "REST": c.Resolve<RestPublisher>(); break; default: throw new NotSupportedException(); } }).As<IPublisher>(); 

2. 使用命名注冊

    builder.RegisterType<DbPublisher>().Named<IPublisher>("DB"); builder.RegisterType<RestPublisher>().Named<IPublisher>("REST"); builder.Register(c => { var index = c.Resolve<IIndex<String, IPublisher>>(); return index[Defs.AppSettings.PublisherType] }.As<IPublisher>(); 

3. 有條件的注冊

   如果在注冊過程中定義了Defs.AppSettings.PublisherType則可以簡單地有條件地注冊您的依賴項：

    switch(Defs.AppSettings.PublisherType){ case "DB": builder.RegisterType<DbPublisher>().As<IPublisher>(); break; case "REST": builder.RegisterType<RestPublisher>().As<IPublisher>(); break; default: throw new NotSupportedException(); }