asp.net中应用websocket

1.连续找了几天解决ajax轮询在用户量多的时候卡死浏览器的方案，comet、SignalR等等。都没有得到满意的解决，最后还是用了websocket临时解决了

2.解决方案，还是需要用到.net framework 4.5版本下  IHttphandler

 1   public void ProcessRequest(HttpContext context)
 2         {
 3             if (context.IsWebSocketRequest)
 4             {
 5                 context.AcceptWebSocketRequest(DoRespond);
 6             }
 7         }
 8 private async Task DoRespond(AspNetWebSocketContext context)
 9         {
10             System.Net.WebSockets.WebSocket socket = context.WebSocket;
11             while (true)
12             {
13                 ArraySegment<byte> buffer = new ArraySegment<byte>(new byte[1024]);
14                 WebSocketReceiveResult result = await socket.ReceiveAsync(buffer, CancellationToken.None);
15                 if (socket.State == WebSocketState.Open)
16                 {
17                     string userMessage = Encoding.UTF8.GetString(buffer.Array, 0, result.Count);
18                     userMessage = "测试消息 : " + userMessage ;
19                     buffer = new ArraySegment<byte>(Encoding.UTF8.GetBytes(userMessage));
20                     await socket.SendAsync(buffer, WebSocketMessageType.Text, true, CancellationToken.None);
21                 }
22                 else
23                 {
24                     break;
25                 }
26             }
27         }

3.界面端，就可以用手动调用，或者结合一个js计时器 即可实现，服务端不断推送消息过来，打开Chrome调试  并不会看到有向后台发起的请求。测试相同用户数量后，比以前的ajax轮询 的效率高了很多。   还需研究 用更简便、科学的方式解决

 1   var socket;
 2
 3         $(document).ready(function () {
 4             if (!Modernizr.websockets)
 5             {
 6                 alert("This browser does not support web sockets");
 7             }
 8
 9             socket = new WebSocket("ws://localhost:49464/WebSocketHandler.ashx");
10
11             socket.addEventListener("open", function (evt) {
12                 $("#divHistory").append(‘<h3>Connection Opened with the server.</h3>‘);
13             }, false);
14
15             socket.addEventListener("close", function (evt) {
16                 $("#divHistory").append(‘<h3>Connection was closed. :‘ + evt.reason + ‘</h3>‘);
17             }, false);
18
19             socket.addEventListener("message", function (evt) {
20                 $("#divHistory").append(‘<h3>‘ + evt.data + ‘</h3>‘);
21             }, false);
22
23             socket.addEventListener("error", function (evt) {
24                 alert(‘Error : ‘ + evt.message);
25             }, false);
26             var rtimer;
27             function loadRiskWindow() {
28                 //rtimer = window.setInterval("LoadMyFundsWork()", 3000);
29             }