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
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Public Class WebForm2Class WebForm2
Inherits System.Web.UI.Page
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Web 窗体设计器生成的代码#Region " Web 窗体设计器生成的代码 "
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'该调用是 Web 窗体设计器所必需的。
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<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()Sub InitializeComponent()
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End Sub
Protected WithEvents dListParent As System.Web.UI.WebControls.DropDownList
Protected WithEvents dListChild As System.Web.UI.WebControls.DropDownList
Protected WithEvents Button1 As System.Web.UI.WebControls.Button
Protected WithEvents Label1 As System.Web.UI.WebControls.Label
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'注意: 以下占位符声明是 Web 窗体设计器所必需的。
'不要删除或移动它。
Private designerPlaceholderDeclaration As System.Object
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Private Sub Page_Init()Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
'CODEGEN: 此方法调用是 Web 窗体设计器所必需的
'不要使用代码编辑器修改它。
InitializeComponent()
End Sub
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#End Region
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Private Sub Page_Load()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
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Protected Sub bindPrivance()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
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Protected Sub BindDrop()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
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Protected Sub BindParent()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
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Protected Sub BindChild()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
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''*******************************************************************************************************
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Private Sub Button1_Click()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
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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..