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Defs.AppSettings.PublisherType在注册过程中定义,您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(); 
   }