SignalR 2.0更改Json Serializer以支持派生类型对象

Question

请注意,我在这里明确地引用了SignalR 2.0 ...我已经看到了一些(讨厌的)方法用于SignalR 1.1/1.2 ......但是还没有用于2.0.

有没有人在更改SignalR 2.0默认的json序列化程序以启用派生类型的发送方面有任何成功？根据我读到的有关SignalR 2.0的内容,这应该是可能的,但是,我没有运气,也没有在任何地方找到完整的例子.

这是我开始的方式...任何帮助将不胜感激.

我的Startup.cs

    [assembly: OwinStartup(typeof(SignalRChat.Startup))]
    namespace SignalRChat
    {

        public class Startup
        {
            public void Configuration(IAppBuilder app)
            {
                // this should allow the json serializer to maintain the object structures
                var serializer = new JsonSerializer()
                {
                    PreserveReferencesHandling = PreserveReferencesHandling.Objects,
                    TypeNameHandling = TypeNameHandling.Objects,
                    TypeNameAssemblyFormat = FormatterAssemblyStyle.Simple
                };

                // register it so that signalr can pick it up
                GlobalHost.DependencyResolver.Register(typeof(JsonSerializer), () => serializer);

                app.MapSignalR();
            }
        }
    }

Hub上的方法

    public void AddStock(Stock stock)
    {
        string stockType = stock.GetType().ToString();
        Console.WriteLine("The type of stock we got was: " + stockType);
    }

我的控制台测试应用程序(这个发布到中心)

    myDataHub.Invoke("AddStock", new NyseStock()
    {
        Company = "Microsoft",
        NyseSymbol = "MSFT"
    });

    myDataHub.Invoke("AddStock", new DaxStock()
    {
        Company = "Microsoft",
        DaxSymbol = "DMSFT"
    });

只是为了衡量Stock.cs

    namespace Messages
    {
        public class Stock
        {
            public string Company
            {
                get;
                set;
            }
            public decimal Price
            {
                get;
                set;
            }
        }

        public class NyseStock : Stock
        {
            public string NyseSymbol
            {
                get;
                set;
            }
        }

        public class DaxStock : Stock
        {
            public string DaxSymbol
            {
                get;
                set;
            }
        }
    }

我的第一个倾向是我忽略了在客户端设置序列化器.所以我在创建连接之后但在创建集线器代理之前添加了以下内容:

    myConnection = new HubConnection("http://localhost:64041/");
    // Update the serializer to use our custom one
    myConnection.JsonSerializer = new JsonSerializer()
    {
         PreserveReferencesHandling = PreserveReferencesHandling.Objects,
         TypeNameHandling = TypeNameHandling.Objects,
         TypeNameAssemblyFormat = FormatterAssemblyStyle.Simple
    };

    //Make proxy to hub based on hub name on server
    myDataHub = myConnection.CreateHubProxy("DataHub");

但是,这导致了一个InvalidOperationException(由于连接处于断开连接状态,因此无法发送数据.在发送任何数据之前调用start.)在myDataHub.Invoke(..)调用期间.

Answer 1

问这个问题已经有一段时间了.为了将来参考,myConnection.Start()需要在创建代理之后调用方法,如下所示

myConnection = new HubConnection(endpoint);

proxy = _conn.CreateHubProxy("DataHub");
proxy.On<string>("ServerEvent", ClientHandler);

myConnection.Start();

proxy.Invoke("hubMethod", ...);