三级联动

之前写了一篇2级联动的，将其修改，就可以得到3级联动菜单。

BigClass
    
        表结构：
            
        测试数据：
                 

SmallClass1

        表结构：
           
         测试数据：
            

SmallClass2

        表结构：
           
        测试数据：
           

aspx页面：

           
aspx代码：

<% @ Page language="c#" Codebehind="liandong_three.aspx.cs" AutoEventWireup="false" Inherits="AspNetTest.Common.liandong_three"  %>
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"  >
< HTML >
     < HEAD >
         < title > liandong_three </ title >
         < meta  content ="Microsoft Visual Studio .NET 7.1"  name ="GENERATOR" >
         < meta  content ="C#"  name ="CODE_LANGUAGE" >
         < meta  content ="JavaScript"  name ="vs_defaultClientScript" >
         < meta  content ="http://schemas.microsoft.com/intellisense/ie5"  name ="vs_targetSchema" >
         < script  language ="javascript" >
        function change1()
        {
            var obj = document.Form1.DropDownList1;
            if(obj.selectedIndex == 0)
            {
                document.Form1.DropDownList2.length =1;
                return;
            }
            var bigClassId = obj.options[obj.selectedIndex].value;
            var obj = document.Form1.DropDownList2;
            obj.length = 0;
            obj.options[0] = new Option("=选择小类1=", "");
            var len = 0;
            for(var i=0; i<arrSmallClass1.length; i++)
            {
                if(arrSmallClass1[i][2] == bigClassId)
                {
                    obj.options[++len] = new Option(arrSmallClass1[i][1], arrSmallClass1[i][0]);
                }
            }
        }        
        function change2()
        {
            var obj = document.Form1.DropDownList2;
            if(obj.selectedIndex == 0)
            {
                document.Form1.DropDownList3.length =1;
                return;
            }
            var smallClassId1 = obj.options[obj.selectedIndex].value;
            var obj = document.Form1.DropDownList3;
            obj.length = 0;
            obj.options[0] = new Option("=选择小类2=", "");
            var len = 0;
            for(var i=0; i<arrSmallClass2.length; i++)
            {
                if(arrSmallClass2[i][2] == smallClassId1)
                {
                    obj.options[++len] = new Option(arrSmallClass2[i][1], arrSmallClass2[i][0]);
                }
            }
        }

         </ script >
     </ HEAD >
     < body  MS_POSITIONING ="GridLayout" >
         < form  id ="Form1"  method ="post"  runat ="server" >
             < FONT  face ="宋体" >
                 < asp:DropDownList  id ="DropDownList1"  style ="Z-INDEX: 100; LEFT: 40px; POSITION: absolute; TOP: 40px"
                    runat ="server" ></ asp:DropDownList >
                 < asp:DropDownList  id ="DropDownList3"  style ="Z-INDEX: 103; LEFT: 216px; POSITION: absolute; TOP: 40px"
                    runat ="server" ></ asp:DropDownList >
                 < asp:DropDownList  id ="DropDownList2"  style ="Z-INDEX: 102; LEFT: 128px; POSITION: absolute; TOP: 40px"
                    runat ="server" ></ asp:DropDownList ></ FONT ></ form >
     </ body >
</ HTML >

cs代码：

  1 using  System;
  2 using  System.Text;
  3 using  System.Collections;
  4 using  System.ComponentModel;
  5 using  System.Data;
  6 using  System.Data.SqlClient;
  7 using  System.Drawing;
  8 using  System.Web;
  9 using  System.Web.SessionState;
 10 using  System.Web.UI;
 11 using  System.Web.UI.WebControls;
 12 using  System.Web.UI.HtmlControls;
 13
 14 namespace  AspNetTest.Common
 15 {
 16    /**//// <summary>
 17    /// liandong_three 的摘要说明。
 18    /// </summary>
 19    public class liandong_three : System.Web.UI.Page
 20    {
 21        protected System.Web.UI.WebControls.DropDownList DropDownList1;
 22        protected System.Web.UI.WebControls.DropDownList DropDownList2;
 23        protected System.Web.UI.WebControls.DropDownList DropDownList3;
 24    
 25        private void Page_Load(object sender, System.EventArgs e)
 26        {
 27            if(!IsPostBack)
 28            {
 29                BindDDLCreateJsdArray();
 30            }
 31            // 在此处放置用户代码以初始化页面
 32        }
 33        private void BindDDLCreateJsdArray()
 34        {
 35            string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"];
 36            SqlConnection conn = new SqlConnection(ConnectionString);
 37            string sql = "select b.d_name as bname,b.d_id as bid,s.d_id as sid,s.d_name as sname,ss.d_id as ssid,ss.d_name as ssname from SmallClass1 s,BigClass b,SmallClass2 ss where b.d_id=s.d_classid and s.d_id=ss.d_classid";
 38            SqlCommand cmd = new SqlCommand(sql, conn);
 39            conn.Open();            
 40            SqlDataReader dr = cmd.ExecuteReader();
 41            StringBuilder sb = new StringBuilder();
 42            sb.Append("<script language=javascript>/n");
 43            //定义JS数组
 44            sb.Append("var arrSmallClass2 = new Array();/n");
 45            sb.Append("var arrSmallClass1 = new Array();/n");
 46            ListItem lt = new ListItem("=选择大类=", "");
 47            DropDownList1.Items.Add(lt);
 48            lt = new ListItem("=选择小类1=", "");
 49            DropDownList2.Items.Add(lt);
 50            lt = new ListItem("=选择小类2=", "");
 51            DropDownList3.Items.Add(lt);
 52            int i = 0;
 53            int j = 0;
 54            int PreBigClassId = 0;
 55            int PreSmallClass1Id = 0;
 56            while(dr.Read())
 57            {
 58                string BigClassName = dr["bname"].ToString();
 59                int BigClassId = Convert.ToInt32(dr["bid"].ToString());
 60                string SmallClass1Name = dr["sname"].ToString();
 61                int SmallClass1ID = Convert.ToInt32(dr["sid"].ToString());
 62                string SmallClass2Name = dr["ssname"].ToString();
 63                int SmallClass2ID = Convert.ToInt32(dr["ssid"].ToString());
 64                lt = new ListItem(BigClassName, BigClassId.ToString());
 65                //防止创建重复值
 66                if(BigClassId != PreBigClassId)
 67                {
 68                    DropDownList1.Items.Add(lt);
 69                    PreBigClassId = BigClassId;
 70                }
 71                lt = new ListItem(SmallClass1Name, SmallClass1ID.ToString());
 72                if(SmallClass1ID != PreSmallClass1Id)
 73                {
 74                    DropDownList2.Items.Add(lt);
 75                    PreSmallClass1Id = SmallClass1ID;
 76                    /**//*
 77                    给JS数组赋值。
 78                    注意：JS中不能直接创建二维数组，要创建可以这样
 79                          var arrTest = new Array();
 80                          arrTest[0] = new Array();
 81                          arrTest[0][0] = 1
 82                    */
 83                    sb.Append("arrSmallClass1["+ j +"] = new Array();/n");
 84                    sb.Append("arrSmallClass1["+ j +"][0] = " + SmallClass1ID.ToString() + ";/n");
 85                    sb.Append("arrSmallClass1["+ j +"][1] = /"" + SmallClass1Name + "/";/n");
 86                    sb.Append("arrSmallClass1["+ j +"][2] = " + BigClassId + ";/n");
 87                    j++;
 88                }
 89                sb.Append("arrSmallClass2["+ i +"] = new Array();/n");
 90                sb.Append("arrSmallClass2["+ i +"][0] = " + SmallClass2ID.ToString() + ";/n");
 91                sb.Append("arrSmallClass2["+ i +"][1] = /"" + SmallClass2Name + "/";/n");
 92                sb.Append("arrSmallClass2["+ i +"][2] = " + SmallClass1ID + ";/n");
 93                i++;
 94            }
 95            sb.Append("</script>");
 96            //将JS字符串输出到客户端
 97            Page.Response.Write(sb.ToString());
 98            //大类change事件
 99            DropDownList1.Attributes.Add("onchange", "change1();change2()");
100            //小类1change事件
101            DropDownList2.Attributes.Add("onchange", "change2();");
102        }
103        Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码
104        override protected void OnInit(EventArgs e)
105        {
106            //
107            // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
108            //
109            InitializeComponent();
110            base.OnInit(e);
111        }
112        
113        /**//// <summary>
114        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
115        /// 此方法的内容。
116        /// </summary>
117        private void InitializeComponent()
118        {    
119            this.Load += new System.EventHandler(this.Page_Load);
120
121        }
122        #endregion
123    }
124}
125

 

 

http://jiny-z.cnblogs.com/archive/2006/03/20/354371.html