使用SignalR和MVC5实时聊天

SignalR是一种可用来简化交互式实时多用户Web应用程序开发的框架，该框架充分应用了异步技术带来的优势，可用来实现性能最好的即时性应用。

1.创建MVC5项目

图片说明

2.添加SignalR包

图片说明

3.创建ChatHub类

using Microsoft.AspNet.SignalR;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Web;

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

        public void Send(string name, string message)
        {
            // Call the addNewMessageToPage method to update clients.
            Clients.All.addNewMessageToPage(name, message);
        }
    }
}

4.修改Startup类

using Microsoft.Owin;
using Owin;

[assembly: OwinStartupAttribute(typeof(SignalRChat.Startup))]
namespace SignalRChat
{
    public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // Any connection or hub wire up and configuration should go here
            app.MapSignalR();
            ConfigureAuth(app);
        }

    }
}

5.创建相应的action以及视图

        public ActionResult Chat()
        {
            return View();
        }

视图代码：

@{
    ViewBag.Title = "Chat";
}
<h2>Chat</h2>
<div class="container">
    <input type="text" id="message" />
    <input type="button" id="sendmessage" value="Send" />
    <input type="hidden" id="displayname" />
    <ul id="discussion"></ul>
</div>
@section scripts {
    <!--Script references. -->
    <!--The jQuery library is required and is referenced by default in _Layout.cshtml. -->
    <!--Reference the SignalR library. -->
    <!--<script src="~/Scripts/jquery.signalR-2.1.0.min.js"></script>-->
    <script src="~/Scripts/jquery.signalR-2.4.1.min.js"></script>
    <!--Reference the autogenerated SignalR hub script. -->
    <script src="~/signalr/hubs"></script>
    <!--SignalR script to update the chat page and send messages.-->
    <script>
        $(function () {
            // Reference the auto-generated proxy for the hub.
            var chat = $.connection.chatHub;
            // Create a function that the hub can call back to display messages.
            chat.client.addNewMessageToPage = function (name, message) {
                // Add the message to the page.
                $('#discussion').append('<li><strong>' + htmlEncode(name)
                    + '</strong>: ' + htmlEncode(message) + '</li>');
            };
            // Get the user name and store it to prepend to messages.
            $('#displayname').val(prompt('Enter your name:', ''));
            // Set initial focus to message input box.
            $('#message').focus();
            // Start the connection.
            $.connection.hub.start().done(function () {
                $('#sendmessage').click(function () {
                    // Call the Send method on the hub.
                    chat.server.send($('#displayname').val(), $('#message').val());
                    // Clear text box and reset focus for next comment.
                    $('#message').val('').focus();
                });
            });
        });
        // This optional function html-encodes messages for display in the page.
        function htmlEncode(value) {
            var encodedValue = $('<div />').text(value).html();
            return encodedValue;
        }
    </script>
}