using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace SignalRChat
{
    public interface IMyClient
    {
        Task SayAsync(Message message);

    }

    public class Message
    {
        public string Titel { get; set; }

        public string Content { get; set; }
    }
}
 

using Microsoft.AspNetCore.SignalR;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace SignalRChat
{
    public class ChatHub : Hub<IMyClient>
    {
        public async Task SendMessage(string user, string message)
        {
            //await Clients.All.SendAsync("ReceiveMessage", user, message);
            await Clients.Groups<IMyClient>("001house").SayAsync(new Message { Titel = "hello word", Content = "中國_" });
            await Clients.All.SayAsync(new Message { Titel = "hello word", Content = "中國" });
        }

        public override Task OnConnectedAsync()
        {
            var connectionId = Context.ConnectionId;
            Groups.AddToGroupAsync(connectionId, "001house");

            return base.OnConnectedAsync();
        }
    }
}
 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace SignalRChat
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddDistributedRedisCache(options =>
            {
                options.Configuration = "127.0.0.1:6379,defaultDatabase=1,connectTimeout=1000,connectRetry=1,syncTimeout=10000";
            });
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            services.AddSignalR().AddRedis("127.0.0.1:6379,defaultDatabase=1,connectTimeout=1000,connectRetry=1,syncTimeout=10000");

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
            }

            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("/chatHub");
            });

            app.UseMvc();
        }
    }
}
 

"use strict";

var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();

connection.on("ReceiveMessage", function (user, message) {
    var msg = message.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
    var encodedMsg = user + " says " + msg;
    var li = document.createElement("li");
    li.textContent = encodedMsg;
    document.getElementById("messagesList").appendChild(li);
});

connection.on("SayAsync", function (message) {
    var value = message;
    var msg = message.content.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
    var encodedMsg = " says： " + msg;
    var li = document.createElement("li");
    li.textContent = encodedMsg;
    document.getElementById("messagesList").appendChild(li);
});

connection.start().catch(function (err) {
    return console.error(err.toString());
});

document.getElementById("sendButton").addEventListener("click", function (event) {
    var user = document.getElementById("userInput").value;
    var message = document.getElementById("messageInput").value;
    connection.invoke("SendMessage", user, message).catch(function (err) {
        return console.error(err.toString());
    });
    event.preventDefault();
});

@page
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}
<div class="container">
    <div class="row">&nbsp;</div>
    <div class="row">
        <div class="col-6">&nbsp;</div>
        <div class="col-6">
            User..........<input type="text" id="userInput" />
            <br />
            Message...<input type="text" id="messageInput" />
            <input type="button" id="sendButton" value="Send Message" />
        </div>
    </div>
    <div class="row">
        <div class="col-12">
            <hr />
        </div>
    </div>
    <div class="row">
        <div class="col-6">&nbsp;</div>
        <div class="col-6">
            <ul id="messagesList"></ul>
        </div>
    </div>
</div>
<script src="~/lib/signalr/signalr.js"></script>
<script src="~/js/chat.js"></script>