JQuery实现简洁的服务器轮询效果实例_

1、JQuery实现简洁的服务器轮询效果实例_ 本文实例讲解并描述了JQuery实现简洁的服务器轮询效果。分享给大家供大家参考，具体如下： 许多论坛都有进入后，弹出提示，说有多少封邮件没有看，或者是一个oa系统，进入后，提示有多少个任务没有做。每隔一段时间会提示一次，但是如何实现呢。其实，利用jquery的话，会比较简洁，核心元素就是json格式解析和setInterval()函数。下面一起来实现： 首先，我们default.aspx的页面如下所示： % Page Language=C# AutoEventWireup=true CodeFile=Default.aspx.cs Inherits=

2、_Default % !DOCTYPE html PUBLIC -/W3C/DTD XHTML 1.0 Transitional/EN l1/DTD/xhtml1-transitional.dtd html xmlns=l head runat=server title服务器轮询/title link href=Content/jquery-ui-1.7.2.custom.css rel=stylesheet type=text/css / link href=Content/ui.jqgrid.css rel=stylesheet type=text/css / script src=Scr

3、ipts/jquery-1.3.2.min.js type=text/javascript/script script src=js/i18n/grid.locale-en.js type=text/javascript/script script src=js/jquery.jqGrid.min.js type=text/javascript/script script src=js/src/grid.base.js type=text/javascript/script script type=text/javascript function showUnreadNews() $(docu

4、ment).ready(function() $.ajax( type: GET, url: Result.ashx, dataType: json, success: function(msg) /alert(msg); $.each(msg, function(id, title) $(#news).append(a href=detailnews.aspx?id= + id + + title + /abr); ); ); ); setInterval(showUnreadNews(),5000); /script /head body form id=form1 runat=serve

5、r div id=news /div /form /body /html 上面代码主要利用ajax函数向Result.ashx页面发出ajax恳求，然后由Result.ashx这个页面返回json数据，并进行解析，最终利用setInterval（）函数实现轮询效果，具体的Result.ashx页面代码如下： % WebHandler Language=C# Class=Result % using System; using System.Web; using System.Text; using System.Data.SQLite; using System.Data; public cl

6、ass Result : IHttpHandler public void ProcessRequest (HttpContext context) string sql = select * from Content where NewsFlag=0; DataTable dt = new DataTable(); using (SQLiteConnection conn = new SQLiteConnection(InitSQLite().Connection) SQLiteDataAdapter sda = new SQLiteDataAdapter(sql, conn); sda.F

7、ill(dt); string jsonStr = GetJson(dt); context.Response.ContentType = text/json; context.Response.Buffer = true; context.Response.ExpiresAbsolute = DateTime.Now.AddDays(-1); context.Response.AddHeader(pragma, no-cache); context.Response.AddHeader(cache-control, ); context.Response.CacheControl = no-

8、cache; context.Response.Write(jsonStr); public static string GetJson(DataTable dt) StringBuilder jsonBuilder = new StringBuilder(); jsonBuilder.Append(); for (int i = 0; i dt.Rows.Count; i+) jsonBuilder.Append( dt.RowsiNewsID.ToString() + : + dt.RowsiNewsTitle.ToString()+,); jsonBuilder.Remove(jsonB

9、uilder.Length - 1, 1); jsonBuilder.Append(); return jsonBuilder.ToString(); public Sqlite InitSQLite() Sqlite _sqLite = new Sqlite(); _sqLite.ConnetStringBuilder.DataSource = AppDomain.CurrentDomain.BaseDirectory + News.db3; _sqLite.ConnetStringBuilder.Pooling = true; _sqLite.ConnetStringBuilder.FailIfMissing = true; _sqLite.ConnetStringBuilder.UseUTF16Encoding = true; return _sqLite; public bool IsReusable get