Question

我正在尝试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种解决方案来实现您的目标。

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>();

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>();

条件注册

如果在注册过程中定义Defs.AppSettings.PublisherType，您只需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(); 
}

解决条件依赖关系autofac

1 个答案: