本片文章为练习，项目中不会这样写：
一：涉及到的知识点：
jQuery Dom操作
jQuery Ajax操作
ASP.net中的json操作
二：用了自动代码生成器
1.Dal层的代码：
public static partial class BranchTwoService
{
/// <summary>
/// 根据一级机构的ID得二级机构列表
/// </summary>
/// <param name="branchOneId">1级机构ID</param>
/// <returns></returns>
public static IList<BranchTwo> GetBranchTwoByBranchOneId(int branchOneId)
{
string strsql = "select * from BranchTwo where BranchOneNo=" + branchOneId;
return GetBranchTwosBySql(strsql);
}
}
public static partial class BranchThirdService
{
/// <summary>
/// 根据二级机构的ID得三级机构列表
/// </summary>
/// <param name="branchTwoId">2级机构ID</param>
/// <returns></returns>
public static IList<BranchThird> GetBranchThirdByBranchTwoId(int branchTwoId)
{
string strsql = "select * from BranchThird where BranchTwoNo=" + branchTwoId;
return GetBranchThirdsBySql(strsql);
}
}
2.BLL层的代码：
public static partial class BranchTwoManager
{
/// <summary>
/// 根据一级机构的ID得二级机构列表
/// </summary>
/// <param name="branchOneId">1级机构ID</param>
/// <returns></returns>
public static IList<BranchTwo> GetBranchTwoByBranchOneId(int branchOneId)
{
return DAL.BranchTwoService.GetBranchTwoByBranchOneId(branchOneId);
}
}
public static partial class BranchThirdManager
{
/// <summary>
/// 根据二级机构的ID得三级机构列表
/// </summary>
/// <param name="branchTwoId">2级机构ID</param>
/// <returns></returns>
public static IList<BranchThird> GetBranchThirdByBranchTwoId(int branchTwoId)
{
return DAL.BranchThirdService.GetBranchThirdByBranchTwoId(branchTwoId);
}
}
UI层的代码：
protected void Page_Load(object sender, EventArgs e)
{
IList<Models.BranchOne> branchOnes = BLL.BranchOneManager.GetAllBranchOnes();
string json = JsonHelper.Serialize(branchOnes);
Response.Write(json);
}
protected void Page_Load(object sender, EventArgs e)
{
if (Request["branchoneid"] != null)
{
int branchoneId = int.Parse(Request.QueryString["branchoneid"]);
IList<Models.BranchTwo> branchTwos = BLL.BranchTwoManager.GetBranchTwoByBranchOneId(branchoneId);
Response.Write(JsonHelper.Serialize(branchTwos));
}
}
public partial class BranchThirdHandler : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Request["branchtwoid"] != null)
{
int branchtwoId = int.Parse(Request.QueryString["branchtwoid"]);
IList<Models.BranchThird> branchThirds= BLL.BranchThirdManager.GetBranchThirdByBranchTwoId(branchtwoId);
Response.Write(JsonHelper.Serialize(branchThirds));
}
}
}
JQuery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>jQuery+Ajax实战三级下拉列表联动</title>
<script src="Scripts/jquery-1.2.6.js" type="text/javascript"></script>
<%-- <script src="Scripts/jquery-1.2.6-vsdoc-cn.js" type="text/javascript"></script>
--%> <script type="text/javascript">
$(document).ready(function() {
$("#divLoading").ajaxStart(function() { $(this).show(); })
.ajaxSuccess(function() { $(this).hide() })
.ajaxError(function() { $(this).html("数据加载失败!"); });
$.getJSON("BranchOneHandler.aspx", function(data) {
var $cbxBranchOne = $("#cbxBranchOne");
$.each(data, function(i, json) {
var $option = $("<option/>").append(json.branchName).attr("value", json.id);
$cbxBranchOne.append($option);
});
$cbxBranchOne[0].selectedIndex = 0;
$cbxBranchOne.change(function() {
var $cbxBranchTwo = $("#cbxBranchTwo");
$cbxBranchTwo.empty(); //清空options
var branchoneId = $(this).attr("value");
if (branchoneId) {
$.getJSON("BranchTowHandler.aspx", { branchoneid: branchoneId }, function(data) {
$.each(data, function(i, json) {
var $option = $("<option/>").append(json.branchName).attr("value", json.id);
$cbxBranchTwo.append($option);
});
});
}
$cbxBranchTwo.change(function() {
var $cbxBranchThird = $("#cbxBranchThird");
$cbxBranchThird.empty();
var branchtowId = $(this).attr("value");
if (branchtowId) {
$.getJSON("BranchThirdHandler.aspx", { branchtwoid: branchtowId }, function(data) {
$.each(data, function(i, json) {
var $option = $("<option/>").append(json.branchName).attr("value", json.id);
$cbxBranchThird.append($option);
});
});
}
});
});
});
});
</script>
</head>
<body style="text-align:center;padding-top:0px;">
<div id="divLoading" style="50px;height:20px;color;white;background-color:Green;text-align:center;padding-top:3px;position:absolute;top:0px;left:0px;display:none;">Loading...</div>
<form id="form1" runat="server">
<div style="padding-top:30px">
<table id="tbBranch" style=" 361px; border-left-color: #cc00ff; border-bottom-color: #cc00ff; border-top-style: solid; border-top-color: #cc00ff; border-right-style: solid; border-left-style: solid; border-right-color: #cc00ff; border-bottom-style: solid;" border="1">
<tr>
<td colspan="3" style="height: 21px; background-color: #cc00ff" align="center">
<span style="color: #ffffff"><strong>
jQuery+Ajax实战三级下拉列表联动</strong></span></td>
</tr>
<tr>
<td style=" 74px; background-color: #cc00ff; height: 38px;">
一级机构</td>
<td colspan="2" style=" 243px; height: 38px;">
<select id="cbxBranchOne" style=" 171px">
<option selected="selected"></option>
</select></td>
</tr>
<tr>
<td style=" 74px; background-color: #cc00ff; height: 31px;">
二级机构</td>
<td colspan="2" style=" 243px; height: 31px;">
<select id="cbxBranchTwo" style=" 171px">
<option selected="selected"></option>
</select>
</td>
</tr>
<tr>
<td style=" 74px; background-color: #cc00ff; height: 29px;">
三级机构</td>
<td colspan="2" style=" 243px; height: 29px;">
<select id="cbxBranchThird" style=" 171px">
<option selected="selected"></option>
</select>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
用到的帮助类：
using System;
using System.Collections.Generic;
using System.Web;
using System.IO;
using System.Text;
/// <summary>
/// JSON序列化与反序列化辅助类
/// </summary>
public class JsonHelper
{
/// <summary>
/// 用于把对象data序列化为json格式的字符串
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="data"></param>
/// <returns></returns>
public static string Serialize<T>(T data)
{
System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(data.GetType());
using (MemoryStream ms = new MemoryStream())
{
serializer.WriteObject(ms, data);
return Encoding.UTF8.GetString(ms.ToArray());
//ms.Position = 0;
//using (StreamReader sr = new StreamReader(ms))
//{
// return sr.ReadToEnd();
//}
}
}
/// <summary>
/// 用于把json格式的js对象反序列化为C#中的类
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="json"></param>
/// <returns></returns>
public static T Deserialize<T>(string json)
{
T obj = Activator.CreateInstance<T>();
using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(json)))
{
System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(obj.GetType());
return (T)serializer.ReadObject(ms);
}
}
}