使用SignalR Core将消息从Controller方法发送到Angular

我正在尝试将SignalR用于Asp Net Core 2.1，以便从控制器方法发送消息，该方法从Angular中的测试按钮触发调用 .
我期望的行为是当我单击按钮时，我的服务调用控制器方法，该方法发送测试消息 . 然后，我将简单地记录消息 .

我想在服务中管理它，以避免所有组件中的代码重复 .

我已经阅读了一些例子this question about using SignalR in a service（我已经使用了第二个解决方案）和this article和the official docs但是即使应用这些概念它似乎也不起作用 .
（所以，或者我仍然缺少一些东西，但我找不到...）

The client connects to the Message Hub successfully 如果我点击按钮， the method is getting hit 但是 I don't get any message 而我在Chrome控制台中收到此警告：

警告：找不到名为“SendAsync”的客户端方法 .

发送消息的工作正常，问题就在于接收它们......

问题是： what am I doing wrong? Is the error on the back-end side or in the Angular side?

我和你分享我的所有代码 (the button and the service to call the controller method are not relevant since the call to the service goes fine) ：

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
   //...
   services.AddSignalR();
}
//...
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
   //...
   app.UseSignalR(routes =>
   {
      //...
      routes.MapHub<MessageHub>("/messagehub");
      //...
   });
}

MessageHub.cs

public class MessageHub : Hub<ITypedHubClient>
{
    public async Task SendMessage(string user, string message)
    {
        await Clients.All.SendAsync("ReceiveMessage", user, message);
    }
}

public interface ITypedHubClient
{
    Task SendAsync(string title, string name, string message);
}

MessageController.cs

IHubContext<MessageHub, ITypedHubClient> _messageHubContext;

public MessageController(IHubContext<MessageHub, ITypedHubClient> messageHubContext)
{
    _messageHubContext = messageHubContext;
}

[HttpPost("Test")]
public async Task<IActionResult> Test()
{
    try
    {
        await _messageHubContext.Clients.All.SendAsync("ReceiveMessage","test", "test");

        return Ok(true);
    }
    catch (Exception e)
    {
        return BadRequest(e);
    }
}

communication.service.ts

@Injectable()
export class CommunicationService {

  private _hubConnection: HubConnection | undefined;
  public async: any;
  message = '';
  messages: string[] = [];

  private newmessage = new Subject<string>();
  message$ = this.newmessage.asObservable();


  constructor() {
    this._hubConnection = new signalR.HubConnectionBuilder()
      .withUrl('/messagehub')
      //.configureLogging(signalR.LogLevel.Information)
      .configureLogging(signalR.LogLevel.Debug)
      .build();

    this._hubConnection.start().catch(err => console.error(err.toString()));

    this._hubConnection.on('SendMessage', (user: any, message:any) => {
      const received = `Received: ${message}`;
      //this.messages.push(received);
      this.newmessage.next(received);
      console.log("got something new...", received);
    });
  }

  clear() {
    this.newmessage.next("");
  }

  public sendMessage(): void {
    const data = `Sent: ${this.message}`;

    if (this._hubConnection) {
      this._hubConnection.invoke('SendMessage', 'AAA' ,data);
    }
    this.messages.push(data);
  }
}