c# – 使用SignalR Core将控制器方法的消息发送到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,如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,但即使应用这些概念,它似乎也不起作用. (所以,或者我绝对是以错误的方式应用它们,或者仍然缺少某些东西,但我找不到…

客户端成功连接到消息中心,如果我单击该按钮,该方法将被点击但我没有收到任何消息,而是在Chrome控制台中收到此警告：

Warning: No client method with the name ‘SendAsync’ found.

发送消息很好,问题就在于接收它们……

问题是：我做错了什么？是后端还是Angular端的错误？

我与你分享我的所有代码(调用控制器方法的按钮和服务是不相关的,因为对服务的调用很顺利)：

> 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);
  }
}

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

IHubContext<MessageHub,ITypedHubClient> _messageHubContext;

    public async Task<IActionResult> Test()
    {
        await _messageHubContext.Clients.All.SendMessageToClient("test","test");
        return Ok("ok");
    }

_hubConnection.on('SendMessageToClient',(title,message) => {
    const received = `title: ${title},name: ${user},message: ${message}`;
    console.log(received);
});

public class MessageHub : Hub
{
    public async Task SendMessage(string title,string message)
    {
        await Clients.All.SendAsync("SendMessageToClient",title,message);
    }
}