Asp.net使用SignalR实现酷炫端对端聊天功能

 public interface IHubConnectionContext<T>
 {
 T All { get; } // 代表所有客户端

 T AllExcept(params string[] excludeConnectionIds); // 除了参数中的所有客户端
 T Client(string connectionId); // 特定的客户端，这个方法也就是我们实现端对端聊天的关键
 T Clients(IList<string> connectionIds); // 参数中的客户端端
 T Group(string groupName, params string[] excludeConnectionIds); // 指定客户端组，这个也是实现群聊的关键所在
 T Groups(IList<string> groupNames, params string[] excludeConnectionIds);
 T User(string userId); // 特定的用户
 T Users(IList<string> userIds); // 参数中的用户
 }

public class ChatHub : Hub
 {
 // 静态属性
 public static List<UserInfo> OnlineUsers = new List<UserInfo>(); // 在线用户列表

 /// <summary>
 /// 登录连线
 /// </summary>
 /// <param name="userId">用户Id</param>
 /// <param name="userName">用户名</param>
 public void Connect(string userId, string userName)
 {
 var connnectId = Context.ConnectionId;

 if (OnlineUsers.Count(x => x.ConnectionId == connnectId) == 0)
 {
 if (OnlineUsers.Any(x => x.UserId == userId))
 {
 var items = OnlineUsers.Where(x => x.UserId == userId).ToList();
 foreach (var item in items)
 {
 Clients.AllExcept(connnectId).onUserDisconnected(item.ConnectionId, item.UserName);
 }
 OnlineUsers.RemoveAll(x => x.UserId == userId);
 }

 //添加在线人员
 OnlineUsers.Add(new UserInfo
 {
 ConnectionId = connnectId,
 UserId = userId,
 UserName = userName,
 LastLoginTime = DateTime.Now
 });
 }

 // 所有客户端同步在线用户
 Clients.All.onConnected(connnectId, userName, OnlineUsers);
 }


 /// <summary>
 /// 发送私聊
 /// </summary>
 /// <param name="toUserId">接收方用户连接ID</param>
 /// <param name="message">内容</param>
 public void SendPrivateMessage(string toUserId, string message)
 {
 var fromUserId = Context.ConnectionId;

 var toUser = OnlineUsers.FirstOrDefault(x => x.ConnectionId == toUserId);
 var fromUser = OnlineUsers.FirstOrDefault(x => x.ConnectionId == fromUserId);

 if (toUser != null && fromUser != null)
 { 
 // send to 
 Clients.Client(toUserId).receivePrivateMessage(fromUserId, fromUser.UserName, message);

 // send to caller user
 // Clients.Caller.sendPrivateMessage(toUserId, fromUser.UserName, message);
 }
 else
 {
 //表示对方不在线
 Clients.Caller.absentSubscriber();
 }
 }

 /// <summary>
 /// 断线时调用
 /// </summary>
 /// <param name="stopCalled"></param>
 /// <returns></returns>
 public override Task OnDisconnected(bool stopCalled)
 {
 var user = OnlineUsers.FirstOrDefault(u => u.ConnectionId == Context.ConnectionId);

 // 判断用户是否存在,存在则删除
 if (user == null) return base.OnDisconnected(stopCalled);

 Clients.All.onUserDisconnected(user.ConnectionId, user.UserName); //调用客户端用户离线通知
 // 删除用户
 OnlineUsers.Remove(user);


 return base.OnDisconnected(stopCalled);
 }
 }

 <script type="text/javascript">
 var systemHub = $.connection.chatHub;
 / 连接IM服务器成功
 // 主要是更新在线用户
 systemHub.client.onConnected = function (id, userName, allUsers) {
 var node = chatCore.node, myf = node.list.eq(0), str = '', i = 0;
 myf.addClass('loading');
 onlinenum = allUsers.length;
 if (onlinenum > 0) {
 str += '<li class="ChatCore_parentnode ChatCore_liston">'
 + '<h5><i></i><span class="ChatCore_parentname">在线用户</span><em class="ChatCore_nums">（' + onlinenum + '）</em></h5>'
 + '<ul id="ChatCore_friend_list" class="ChatCore_chatlist">';
 for (; i < onlinenum; i++) {
 str += '<li id="userid-' + allUsers[i].UserID + '" data-id="' + allUsers[i].ConnectionId + '" class="ChatCore_childnode" type="one"><img src="https://www.gxlcms.com/Content/Images/001.jpg?' + allUsers[i].UserID + '" class="ChatCore_oneface"><span class="ChatCore_onename">' + allUsers[i].UserName + '(' + ')</span><em class="ChatCore_time">' + allUsers[i].LoginTime + '</em></li>';
 }
 str += '</ul></li>';
 myf.html(str);
 } else {
 myf.html('<li class="ChatCore_errormsg">没有任何数据</li>');
 }
 myf.removeClass('loading');
 };
 //消息传输
 chatCore.transmit = function () {
 var node = chatCore.node, log = {};
 node.sendbtn = $('#ChatCore_sendbtn');
 node.imwrite = $('#ChatCore_write');

 //发送
 log.send = function () {
 var data = {
 content: node.imwrite.val(),
 id: chatCore.nowchat.id,
 sign_key: '', //密匙
 _: +new Date
 };

 if (data.content.replace(/\s/g, '') === '') {
 layer.tips('说点啥呗！', '#ChatCore_write', 2);
 node.imwrite.focus();
 } else {
 //此处皆为模拟
 var keys = chatCore.nowchat.type + chatCore.nowchat.id;

 //聊天模版
 log.html = function (param, type) {
 return '<li class="' + (type === 'me' ? 'ChatCore_chateme' : '') + '">'
 + '<div class="ChatCore_chatuser">'
 + function () {
 if (type === 'me') {
 return '<span class="ChatCore_chattime">' + param.time + '</span>'
 + '<span class="ChatCore_chatname">' + param.name + '</span>'
 + '<img src="' + param.face + '" >';
 } else {
 return '<img src="' + param.face + '" >'
 + '<span class="ChatCore_chatname">' + param.name + '</span>'
 + '<span class="ChatCore_chattime">' + param.time + '</span>';
 }
 }()
 + '</div>'
 + '<div class="ChatCore_chatsay">' + param.content + '<em class="ChatCore_zero"></em></div>'
 + '</li>';
 };

 log.imarea = chatCore.chatbox.find('#ChatCore_area' + keys);

 log.imarea.append(log.html({
 time: new Date().toLocaleString(),
 name: config.user.name,
 face: config.user.face,
 content: data.content
 }, 'me'));
 node.imwrite.val('').focus();
 log.imarea.scrollTop(log.imarea[0].scrollHeight);

 // 调用服务端sendPrivateMessage方法来转发消息
 systemHub.server.sendPrivateMessage(chatCore.nowchat.id, data.content);
 }

 };
 node.sendbtn.on('click', log.send);

 node.imwrite.keyup(function (e) {
 if (e.keyCode === 13) {
 log.send();
 }
 });
 };

 //用户离线
 systemHub.client.onUserDisconnected = function (id, userName) {
 onlinenum = onlinenum - 1;
 $(".ChatCore_nums").html("（" + onlinenum + "）");
 $("#ChatCore_friend_list li[data-id=" + id + "]").remove();
 };
 // 启动连接
 $.connection.hub.start().done(function () {
 systemHub.server.connect(userid, username); // 调用服务端connect方法
 });
 </script>