解決條件依賴關係autofac

Question

我想解決基於條件的依賴關係。

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>()} 
} 

我只是想確定如果這是解決依賴條件的唯一方法。我一直在使用Ninject到目前爲止並正在尋找類似如下：

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

只是想確認我在做正確的事與Autofac

Answer 1

我可以看到3個解決方案，以實現你想要的。

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. 使用名爲註冊

   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. 有條件註冊

   如果Defs.AppSettings.PublisherType在註冊過程中被定義，你可以簡單地有條件註冊你的依賴：

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