大家應該都看到過 GOOGLE 的搜索建議,就是當我們在輸入關鍵詞時,GOOGLE 會根據我們目前已輸入的字顯示相關的關鍵字建議,這就是搜索建議,現在很多網站都實現該友好的功能,如 YAHOO、狗狗搜索等。
實現該功能的思路就是:
在關鍵字輸入框裏,當用戶按鍵彈起時,發送輸入框裏的字符串到服務器。
服務器根據收到客戶端發來的字進入匹配搜索
將匹配用戶已輸入字的記錄回發到客戶端
客戶端收到服務端的響應,輸出建議。
其實就是異步回發(AJAX)。
下面是一個實例,實例實現的是搜索 SQL Server 默認數據庫 Northwind 表 Customers 字段 CustomerID,當用戶要輸入框輸入字時,返回該字段值與用戶輸入的字開頭匹配的記錄,即 CustomerID LIKE '用戶已輸入的字%'。
樣式已設置好,顯示建議的行爲絕對位置,所以該行不會顯示網頁上的內容。
文件名:WordSuggest.aspx
源碼如下:
.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="WordSuggest.aspx.cs" Inherits="WordSuggest" %>
<!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>無標題頁</title>
<style type="text/css">
.CInput{border:solid 1px gray;width:300px}
#divSuggestions{border:solid 1px gray;width:300px;background:#fff;visibility:hidden}
#divSuggestions span{display:block;padding:3px}
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
<h1>搜索建議 DEMO</h1>
<span>http://www.code-studio.net </span>
<hr />
<table style="border-collapse:collapse;"><tr><td><asp:TextBox ID="txtInput" runat="server" CssClass="CInput" onkeyup="sendRqt(this)"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Submit" /></td></tr>
<tr style="position:absolute;"><td><div id="divSuggestions"></div></td></tr></table>
</div>
</form>
<script type="text/javascript">
var xhr;
var isIe=window.navigator.appName.indexOf("Netscape") == -1?true:false;
function $(sElmId){return document.getElementById(sElmId);}
function crtRqt(){
if(window.ActiveXobject)
xhr=new ActiveXObject("Microsoft.XMLHTTP");
else xhr=new XMLHttpRequest();
}
function sendRqt(srcElm){
var sInput=srcElm.value;
if(sInput!=""){
var url="wordsuggest.aspx?t="+new Date().getTime()+"&w="+sInput;
crtRqt();
xhr.onreadystatechange=hdlRsp;
xhr.open("GET",url,true);
xhr.send(null);
}
else $("divSuggestions").style.visibility="hidden";
}
function hdlRsp(){
if(xhr.readyState==4&&xhr.status==200){
var rspText=xhr.responseText;
var oDiv=$("divSuggestions");
if(rspText!=""){
var arrRspText=xhr.responseText.split(',');
var sInnerHtml="";
for(var i=0;i<arrRspText.length;++i){
sInnerHtml+="<span onmouseover='setStyle(this,true)' onmouseout='setStyle(this,false)'"
+" onclick='setInput(this)'>"+arrRspText[i]+"</span>";
}
oDiv.innerHTML=sInnerHtml;
oDiv.style.visibility="visible";
}
else oDiv.style.visibility="hidden";
}
}
function setStyle(srcElm,bOver){
srcElm.style.background=bOver?"orange":"";
}
function setInput(srcElm){
$("<%=txtInput.ClientID %>").value=srcElm.innerHTML;
}
</script>
</body>
</html>
.CS
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class WordSuggest : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string strInput = string.IsNullOrEmpty(Request.QueryString["w"]) ? string.Empty : Request.QueryString["w"];
if (strInput.Trim().Length != 0)
{
Suggeste(strInput);
}
}
private void Suggeste(string originalStr)
{
/* 搜索建議
* 文件名: WordSuggest.aspx
* 功能描述: 根據用戶輸入,在數據庫 Northwind 的表 Customers 查找 CustomerID 字段值匹配的記錄.
*/
SqlConnection conn = new SqlConnection("data source=localhost;database=northwind;user id=sa;password=你的密碼");
string cmdText = "SELECT TOP 10 CustomerID FROM Customers WHERE CustomerID LIKE @w";
SqlParameter para = new SqlParameter("@w", string.Format("{0}%", originalStr));
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = cmdText;
cmd.Parameters.Add(para);
conn.Open();
SqlDataReader reader = cmd.ExecuteReader();
System.Text.StringBuilder sb = new System.Text.StringBuilder();
while (reader.Read())
{
sb.AppendFormat("{0},", reader[0]);
}
reader.Close();
conn.Close();
Response.ContentType = "text/plain";
Response.Clear();
if (sb.Length != 0)
{
Response.Write(sb.ToString().Remove(sb.Length - 1));
}
else
{
Response.Write(string.Empty);
}
Response.Flush();
Response.Close();
}
}