Question

我正在尝试使用Autofac解决不同类的接口的不同实现，原因是我想通过我的消息处理程序中的SignalR集线器向客户端发送更新 - 但是我不想要处理程序成为集线器客户端本身，不同的处理程序需要使用不同的集线器。

我最初看起来像这样：

public class Hub1 : Hub { }
public class Hub2 : Hub { }

public class Handler1 : IHandle<Message1>
{
    private AppData data;
    private IHubContext hubContext;

    public Handler1(AppData data)
    {
        this.data = data;
        this.hubContext = GlobalHost.ConnectionManager.GetHubContext<Hub1>()
    }
}

public class Handler2 : IHandle<Message2>
{
    private AppData data;
    private IHubContext hubContext;

    public Handler2(AppData data)
    {
        this.data = data;
        this.hubContext = GlobalHost.ConnectionManager.GetHubContext<Hub2>()
    }
}

使用Autofac绑定如下：

// Single shared instance of AppData for all handlers
builder.RegisterType<AppData>().AsSelf().SingleInstance();

builder.RegisterType<Handler1>().AsImplementedInterfaces();
builder.RegisterType<Handler2>().AsImplementedInterfaces();

这两个处理程序已经通过Autofac注入了AppData，但我还想注入IHubContext，但我正在努力弄清楚如何去做。

我已更改为要求IHubContext作为处理程序中的构造函数参数：

public class Handler1 : IHandle<Message1>
{
    private AppData data;
    private IHubContext hubContext;

    public Handler1(AppData data, IHubContext hubContext)
    {
        this.data = data;
        this.hubContext = hubContext;
    }
}

我已尝试将IHubContext注册为命名服务并指定处理程序的注册，如下所示：

builder.Register<IHubContext>(_ => GlobalHost.ConnectionManager.GetHubContext<Hub1>())
    .Named<IHubContext>("Hub1Context");

builder.Register<IHubContext>(_ => GlobalHost.ConnectionManager.GetHubContext<Hub2>())
    .Named<IHubContext>("Hub2Context");

builder.RegisterType<Handler1>()
    .WithParameter(ResolvedParameter.ForNamed<IHubContext>("Hub1Context"));

builder.RegisterType<Handler2>()
    .WithParameter(ResolvedParameter.ForNamed<IHubContext>("Hub2Context"));

然而，这会导致异常：

A first chance exception of type 'Autofac.Core.DependencyResolutionException' occurred in Autofac.dll

Additional information: None of the constructors found with 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder' on type 'Handler1' can be invoked with the available services and parameters:

Cannot resolve parameter 'Microsoft.AspNet.SignalR.IHubContext hubContext' of constructor 'Void .ctor(AppData, Microsoft.AspNet.SignalR.IHubContext)'.

我哪里错了？我在过去和Ninject做过类似的事情，只是说了一句话：

kernel.Bind<IHubContext>()
      .ToMethod(_ => GlobalHost.ConnectionManager.GetHubContext<Hub1>())
      .WhenInjectedInto<Handler1>();

使用Autofac解决不同的接口实现

0 个答案: