webform2.aspx
<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm2.aspx.vb" Inherits="salonmaster.WebForm2"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><HTML> <HEAD> <title>WebForm1</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"> //jb函数会根据不同的浏览器初始化个xmlhttp对象 function jb() { var A=null; try { A=new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) { try { A=new ActiveXObject("Microsoft.XMLHTTP"); } catch(oc) { A=null } } if ( !A && typeof XMLHttpRequest != "undefined" ) { A=new XMLHttpRequest() } return A } //下面Go函数是父列表框改变的时候调用，参数是选择的条目 function Go(obj) { //得到选择框的下拉列表的value var svalue = obj.value; //定义要处理数据的页面 var weburl = "webform2.aspx?parent_id="+svalue; //初始化个xmlhttp对象 var xmlhttp = jb(); //提交数据，第一个参数最好为get，第三个参数最好为true xmlhttp.open("get",weburl,true); // alert(xmlhttp.responseText); //如果已经成功的返回了数据 xmlhttp.onreadystatechange=function() { if(xmlhttp.readyState==4)//4代表成功返回数据 { var result = xmlhttp.responseText;//得到服务器返回的数据 //先清空dListChild的所有下拉项 document.getElementById("dListChild").length = 0; //给dListChild加个全部型号的,注意是Option不是option document.getElementById("dListChild").options.add(new Option("所有城市","0")); if(result!="")//如果返回的数据不是空 { //把收到的字符串按照，分割成数组 var allArray = result.split(","); //循环这个数组，注意是从1开始，因为收到的字符串第一个字符是，号，所以分割后第一个数组为空 for(var i=1;i<allArray.length;i++) { //在把这个字符串按照|分割成数组 var thisArray = allArray[i].split("|"); //为dListChild添加条目 document.getElementById("dListChild").options.add(new Option(thisArray[1].toString(),thisArray[0].toString())); } } } } //发送数据，请注意顺序和参数，参数一定为null或者"" xmlhttp.send(null); } </script> </HEAD> <body MS_POSITIONING="GridLayout"> <form id="Form1" method="post" runat="server"> <asp:dropdownlist id="dListParent" style="Z-INDEX: 101; LEFT: 160px; POSITION: absolute; TOP: 56px" runat="server" onchange="Go(this)"> </asp:dropdownlist> <asp:dropdownlist id="dListChild" style="Z-INDEX: 102; LEFT: 304px; POSITION: absolute; TOP: 56px" runat="server"></asp:dropdownlist><asp:button id="Button1" style="Z-INDEX: 103; LEFT: 176px; POSITION: absolute; TOP: 128px" runat="server" Text="提交"></asp:button> <asp:Label id="Label1" style="Z-INDEX: 104; LEFT: 168px; POSITION: absolute; TOP: 24px" runat="server">Label</asp:Label> </form> </body></HTML>后台代码
Imports System.Data.OleDb
Public Class WebForm2
Inherits System.Web.UI.Page
Web 窗体设计器生成的代码
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load ' 在此处放置用户代码以初始化页面 If Not IsPostBack Then bindPrivance() End If BindDrop()
End Sub Protected Sub bindPrivance() Dim conn As New OleDbConnection(ConfigurationSettings.AppSettings("area").ToString) Dim commStr As String = "select * from povince" Dim adp As New OleDbDataAdapter(commStr, conn) Dim ds As New DataSet adp.Fill(ds, "area") dListParent.DataSource = ds.Tables("area").DefaultView dListParent.DataTextField = "province" dListParent.DataValueField = "provinceID" dListParent.DataBind() End Sub Protected Sub BindDrop() '首先我想父dropdownlist也绑定数据库,后面想没必要 'if(!IsPostBack) '{ '绑定父dListParent ' BindParent(); '} '获得传递过来的parent_id值,如果是第一次请求他为null Dim str As String = Request.QueryString("parent_id") Dim str1 As String = dListParent.SelectedValue ' Response.Write(str1) '如果str加个字符串!=原来的字符串则说明触发过dListParent的onchange事件 If str + "abc" <> "abc" Then '绑定 dListChild控件 BindChild(str) '把传来的父DropDownList的value做为参数 Else BindParent(str1) End If End Sub 'BindDrop Protected Sub BindParent(ByVal str As String) '如果是第一次请求或者是刷新这个页面则根据dListParent的值来选择 '把参数转化成int ' Dim i As Integer = Convert.ToInt32(str) dListChild.Items.Clear() dListChild.Items.Add(New ListItem("全部城市", "0")) '得到数据库连接字符串 Dim connStr As String = ConfigurationSettings.AppSettings("area").ToString '初始化个conn对象 Dim conn As New OleDbConnection(connStr) '数据库语句 Dim commStr As String = "select cityID,city from city where father = '" & str & "'" '建立数据库命令对象 Dim comm As New OleDbCommand(commStr, conn) '打开数据库 conn.Open() '执行命令 Dim dr As OleDbDataReader = comm.ExecuteReader() '循环dr，给dListParent添加条目 While dr.Read() dListChild.Items.Add(New ListItem(dr(1).ToString(), dr(0).ToString())) End While '也可以这样 '添加下面这话的意思是当点提交按钮提交窗体的时候第二个dListChild的状态能够得到保存 dListChild.SelectedValue = Request.Form("dListChild") dr.Close() conn.Close() End Sub 'BindParent Protected Sub BindChild(ByVal str As String) '通过js给包括dropdownlist任何控件添加的内容不会被保存状态 '把参数转化成int '定义个字符串用保存从数据库返回的数据 Dim result As String = "" '先清空输出的东西 Response.Clear() Dim connStr As String = ConfigurationSettings.AppSettings("area").ToString Dim conn As New OleDbConnection(connStr) Dim comm As OleDbCommand = conn.CreateCommand() Dim commStr As String = "select cityID,city from city where father = '" & str & "'" comm.CommandText = commStr conn.Open() Dim dr As OleDbDataReader = comm.ExecuteReader() While dr.Read() result += "," + dr(0).ToString() + "|" + dr(1).ToString() End While '把从数据库得到的信息输出到客户端 Response.Write(result) '输出完成关闭Response,以免造成不必要的输出 Response.Flush() Response.Close() dr.Close() conn.Close() End Sub ''******************************************************************************************************* Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If dListChild.SelectedValue = 0 Then Label1.Text = dListParent.SelectedItem.Text Else Label1.Text = dListChild.Items(dListChild.SelectedIndex).Text End If End Sub
End Class呵呵...参考C#联动的.附加上个数据库...不过还没有写三级联运呢..
