Csharp SignalR C# 客户端 HubConnection.On 方法不起作用

我正在try 使用.Net Core Web API(服务器端)和控制台应用程序(客户端)来实现SignalR，以了解其工作原理.

下面是我的starp.cs代码:

public void ConfigureServices(IServiceCollection services)
{

    services.AddControllers();
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "SignalR", Version = "v1" });
    });
    //Service for SignalR
    services.AddSignalR();
    services.AddCors(c =>
    {
        c.AddPolicy("AllowOrigin", options => options.AllowAnyOrigin());
    });
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseSwagger();
        app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "SignalR v1"));
    }

    app.UseHttpsRedirection();

    app.UseRouting();

    app.UseAuthorization();

    app.UseCors(o=>o.AllowAnyOrigin());

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
        //Endpoint map for ChatHub, which I've created
        endpoints.MapHub<ChatHub>("/chathub");
    });
}  

以下是我的ChatHub类:

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

以下是我的控制台应用程序(创建为SignalR客户端):

static async Task Main(string[] args)
       {
           try
           {
               HubConnection connection = new HubConnectionBuilder().WithUrl("https://localhost:44340/chathub").WithAutomaticReconnect().Build();

               await connection.StartAsync();

               if(connection.State == HubConnectionState.Connected)
               {
                   Console.WriteLine("Connected ... Please type message now");
                   var message = "Hey";
                   //Getting hit to SendMessage method defined in  ChatHub Class
                   await connection.InvokeAsync("SendMessage", message);
                   Console.WriteLine(connection.ConnectionId);
                   /*
                    Connection.On is not working and unable to writeline on console.
                    I am expecting result Hey on Console.
                    */
                   connection.On<string>("ReceiveMessage", m =>
                   {
                       Console.WriteLine(m);
                   });
               }
           }
           catch (Exception ex)
           {

               Console.WriteLine(ex.Message);
           }
       }

I am expecting Result : ConnectionId
Hey
But I am getting: ConnectionId