JQuery和IHttpHandler实现自动提示功能（转）

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转自：http://topic.csdn.net/u/20091214/16/0efa4feb-c26c-4544-b512-45fde803497d.html?76771

aspx代码

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %><%--<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">--%><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title>seach</title> <mce:script type="text/javascript" src="jquery.min.js" mce_src="jquery.min.js"></mce:script> <mce:script type="text/javascript"></mce:script> <mce:style type="text/css"></mce:style><style type="text/css" mce_bogus="1"> UL { padding: 0px; LIST-STYLE-TYPE: none; MARGIN: 0px; LIST-STYLE-IMAGE: none; height: 52px; } LI { PADDING-BOTTOM: 0px; LIST-STYLE-TYPE: none; MARGIN: 0px; PADDING-LEFT: 0px; PADDING-RIGHT: 0px; LIST-STYLE-IMAGE: none; PADDING-TOP: 0px} .h_14 { BACKGROUND-IMAGE: url(text_search.jpg); TEXT-ALIGN: left; PADDING-BOTTOM: 1px; LINE-HEIGHT: 26px; MARGIN-TOP: 3px; PADDING-LEFT: 4px; WIDTH: 245px; BACKGROUND-REPEAT: no-repeat; BACKGROUND-POSITION: center 50%; FLOAT: left; HEIGHT: 26px; MARGIN-LEFT: 3px; VERTICAL-ALIGN: middle; OVERFLOW: hidden; MARGIN-RIGHT: 3px; PADDING-TOP: 2px} .h_15 { BORDER-BOTTOM: 0px; BORDER-LEFT: 0px; PADDING-BOTTOM: 0px; LINE-HEIGHT: 20px; PADDING-LEFT: 0px; WIDTH: 240px; PADDING-RIGHT: 0px; DISPLAY: block; FLOAT: left; HEIGHT: 20px; MARGIN-LEFT: 0px; FONT-SIZE: 14px; VERTICAL-ALIGN: middle; BORDER-TOP: 0px; BORDER-RIGHT: 0px; PADDING-TOP: 4px} .h_16 { WIDTH: 57px; FLOAT: left; HEIGHT: 32px; OVERFLOW: hidden; CURSOR: pointer} .sokeyup { Z-INDEX: 10000; BORDER-BOTTOM: #000000 1px solid; POSITION: absolute; BORDER-LEFT: #000000 1px solid; WIDTH: 245px; DISPLAY: none; CLEAR: both; OVERFLOW: hidden; BORDER-TOP: #000000 1px solid; BORDER-RIGHT: #000000 1px solid} .sokeyup_1 { LINE-HEIGHT: 20px; PADDING-LEFT: 4px; WIDTH: 237px; PADDING-RIGHT: 4px; HEIGHT: 20px; CLEAR: both; OVERFLOW: hidden} .sokeyup_2 { LINE-HEIGHT: 20px; WIDTH: 140px; FLOAT: left; HEIGHT: 20px; COLOR: #4c4c4c} .sokeyup_3 { TEXT-ALIGN: right; LINE-HEIGHT: 20px; WIDTH: 97px; FLOAT: right; HEIGHT: 20px; COLOR: #008000} .sokeyup_4 { LINE-HEIGHT: 20px; WIDTH: 237px; HEIGHT: 20px } .sokeyup_5 { LINE-HEIGHT: 20px; FLOAT: right; HEIGHT: 20px; COLOR: #0000cc; CURSOR: pointer; TEXT-DECORATION: underline} </style> </head><body> <form id="form1" runat="server"> <div onclick="keyup_close();"> <ul> <li class="h_14"> <iframe style="display: none" mce_style="display: none" id="if_keyup" name="if_keyup"></iframe> <input id="kw" name="kw" class="h_15" onkeyup="keyup(event)" autocomplete="off" /> <div style="display: none" mce_style="display: none" id="keyup_d" class="sokeyup"> </div> </li> <li class="h_16"> <input style="cursor: pointer" mce_style="cursor: pointer" onclick="so_search();" src="searchbuttom.gif" mce_src="searchbuttom.gif" type="image" /> </li> </ul> </div> </form></body></html>

.ashx代码

<%@ WebHandler Language="C#" Class="JsonHandler" %>using System;using System.Web;using System.Data.SqlClient;using System.Data;public class JsonHandler : IHttpHandler { public void ProcessRequest (HttpContext context) { context.Response.ContentType = "text/plain"; string Key = context.Request["kw"]; if (Key != null && Key != "") { SqlConnection con = new SqlConnection("server=local;database=TPMS;uid=sa;pwd=sa;"); con.Open(); string str = "select distinct username from tbl_users where username like @kw order by username"; SqlCommand com = new SqlCommand(str, con); com.Parameters.Add("@kw", SqlDbType.NVarChar).Value = "%" + Key + "%"; SqlDataReader sdr = com.ExecuteReader(); string htmlstr = ""; int i = 1; while (sdr.Read()) { string kword = sdr["username"].ToString(); //string a = sdr["num"].ToString(); htmlstr += "<ul class='sokeyup_1' onmouseover='keyup_over(" + i + ")' onmouseout='keyup_out(" + i + ")' onclick='keyup_click(" + i + ")' id='u_" + i + "'>"; htmlstr += "<li class='sokeyup_2' id='l_" + i + "'>" + kword + "</li>"; htmlstr += "<li class='sokeyup_3'>" + i + " 结果</li></ul>"; i++; } context.Response.Write(htmlstr); context.Response.End(); sdr.Close(); con.Close(); } } public bool IsReusable { get { return false; } }}

ASP.Net处理Http Request时，使用Pipeline（管道）方式，由各个HttpModule对请求进行处理，然后到达HttpHandler，HttpHandler处理完之后，仍经过Pipeline中各个HttpModule的处理，最后将HTML发送到客户端浏览器中。

生命周期中涉及到几个非常重要的对象：HttpHandler,HttpModule,IHttpHandlerFactory，他们的执行(顺序)大致的执行过程是这样的：client端发送页面请求，被IIS的某个进程截获，它根据申请的页面后缀(.aspx)不同，调用不同的页面处理程序(.asp->asp.dll;.aspx->ISAPI.dll).而页面处理程序在处理过程中，则要经历HttpModule,HttpHandler的处理：前者HttpModule用于页面处理前和处理后的一些事件的处理，后者HttpHandler进行真正的页面的处理。
如前所说，HttpModule会在页面处理前和后对页面进行处理，所以它不会影响真正的页面请求。通常用在给每个页面的头部或者尾部添加一些信息（如版权声明）等.曾经见过一些免费的空间，我们的页面上传上去后，浏览的时候发现，在每个页面的头部和尾部多了很多小广告....,如果理解了HttpModule的原理，要做这个就不是很难了~