解决条件依赖关系autofac

Question

我试图根据条件解决依赖关系。

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>()}
 }

我只是想确定这是否是根据条件解决依赖关系的唯一方法。 到目前为止我一直在使用Ninject，我正在寻找以下内容：

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

只是想确保我使用Autofac做正确的事情

Answer 1

我可以看到3个解决方案来实现你想要的。

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. 使用命名注册

    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. 有条件的注册

   如果在注册过程中定义了Defs.AppSettings.PublisherType则可以简单地有条件地注册您的依赖项：

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