jQuery+Asp.Net实现省市二级联动功能的方法_实用技巧_

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ddlAjax.aspx.cs" Inherits="ThreeAjaxDrop_ddlAjax" %>
 三级联动：==选择省份====选择城市==& amp;nbsp; ==选择县==

 public partial class ThreeAjaxDrop_Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string sql = "select * from province"; string strTemp = "\"text\":\"{0}\",\"value\":\"{1}\""; //构造格式字符串 {"text":"北京","value":"00001"} StringBuilder sb = new StringBuilder(); OleDbDataReader reader = OleDBHelper.ExecuteReader(sql); while (reader.Read()) { string str1 = string.Format(strTemp, reader["province"].ToString(), reader["provinceID"].ToString()); sb.Append("{"+str1+"},"); } reader.Close(); string json = sb.ToString(); Response.Write("["+json.Substring(0,json.Length-1)+"]"); } } 

 public class HandlerDropDownAjax : IHttpHandler { public void ProcessRequest (HttpContext context) { if (context.Request.QueryString["type"] != null && context.Request.QueryString["fid"] != null) { string type = context.Request.QueryString["type"].ToString(); //主要用于识别是查询city还是area表 string fid = context.Request.QueryString["fid"].ToString(); //城市或区域的父ID string sql = "select * from " + type + " where father='" + fid + "'"; //构造数据的类型[{"text":"南昌","value":"0001"},{"text":"上饶","value":"0002"}] //string strTemp = "{\"text\":\"{0}\",\"value\":\"{1}\"}";//这里犯了个错误：直接这样构造会出错，因为大括号里又有格式大括号，解析会出错 string strTemp = "\"text\":\"{0}\",\"value\":\"{1}\""; //构造格式字符串 {"text":"北京","value":"00001"} StringBuilder sb = new StringBuilder(); OleDbDataReader reader = OleDBHelper.ExecuteReader(sql); while (reader.Read()) { string str1 = string.Format(strTemp, reader[2].ToString(), reader[1].ToString()); sb.Append("{" + str1 + "},"); //两边的大括号格式化后加上 } reader.Close(); string json = sb.ToString(); context.Response.Write("[" + json.Substring(0, json.Length - 1) + "]"); //Substring的作用是去掉最后一个'逗号' } } public bool IsReusable { get { return false; } } }