Question

我能够连接到集线器，并且已连接OnConnected和OnDisconnected。他们应该从整数中进行加/减，并使用新值调用客户端回调。我的角度应用程序已成功连接到服务器，但未触发我注册的回调函数。

这是我的Serverhub：

[HubName("online")]
public class OnlineHub : Hub
{
    private static int userCount = 0;

    public override Task OnConnected()
    {
        userCount++;
        Clients.All.listUpdated(userCount);

        return base.OnConnected();
    }

    public override Task OnDisconnected(bool stopCalled)
    {

        userCount--;

        Clients.All.listUpdated(userCount);

        return base.OnDisconnected(stopCalled);
    }
}

这是我的Angular SignalRService：

import { AppSettings } from './../app.settings';
import { EventEmitter, Injectable, OnDestroy } from '@angular/core';

declare const $: any;

@Injectable()
export class SignalRService {

  // Declare the variables
  private onlineHub: any;
  // create the Event Emitter
  public messageReceived: EventEmitter<any>;
  public connectionEstablished: EventEmitter<Boolean>;
  public connectionExists: Boolean;

  constructor(private appSettings: AppSettings) {
    // Setup
    this.connectionEstablished = new EventEmitter<Boolean>();
    this.messageReceived = new EventEmitter<any>();
    this.connectionExists = false;
  }

  // This method gets executed from angular controller
  public initialize(proxyName: string): void {
    this.onlineHub = $.connection.online;

    this.onlineHub.client.listUpdated = function(list: any): void {
      console.log(list);
      this.messageReceived.emit(list);
    };

    this.startConnection();
  }

  private startConnection(): void {
    $.connection.hub.url = this.appSettings.SIGNALR_BASE_URL + '/signalr';
    $.connection.hub.start()
      .done((data: any) => {
        console.log('SignalR Connected with: ' + data.transport.name);
        this.connectionEstablished.emit(true);
        this.connectionExists = true;
      })
      .fail((error: any) => {
        console.log('SignalR could not connect: ' + error);
        this.connectionEstablished.emit(false);
      });
  }

  private registerOnServerEvents() {
    this.onlineHub.client.listUpdated = function(list: any): void {
      console.log(list);
      this.messageReceived.emit(list);
    };
  }
}

我按照文档所述在运行start（）之前注册了我的回调“ listUpdated”，并且$ .connection.hub包含在调用start（）之前的client.listUpdated，因此它应该注册。但是，仍然不会调用OnConnected方法。

Answer 1

我通过将try / catch块中的OnConnected（）和OnDisconnected（）代码括起来并解决了此问题，并创建了一个称为“错误”的客户端方法，该方法将最终的异常返回给客户端。这样，我发现自己遇到了Json序列化问题。

我的集线器现在看起来像这样：

    [HubName("online")]
    public class OnlineHub : Hub
    {
        private static int userCount = 0;


        public override Task OnConnected()
        {
            try
            {
                userCount++;
                Clients.All.listUpdated(userCount);

            }
            catch (Exception exc)
            {
                Clients.All.error(exc);
            }

            return base.OnConnected();
        }

        public override Task OnDisconnected(bool stopCalled)
        {
            try
            {
                userCount--;
                Clients.All.listUpdated(userCount);
            }
            catch (Exception exc)
            {
                Clients.All.error(exc);
            }

            return base.OnDisconnected(stopCalled);
        }
    }

在调用start（）之前，我在js客户端上注册了错误回调：

this.onlineHub.client.error = (exc: any): void => {
  console.log('Error occured:', exc);
};

SignalR Javascript Client回调未触发

1 个答案: