初学者请教一个问题，怎么关联2个dropdownlist
我使用2个dropdownlist，第一个控件里放 蔬菜、水果等选项，我想在第一个控件里选择蔬菜后，第二个控件中显示白菜、萝卜等具体蔬菜名，如果在第一个控件里选择水果后，则在第二个里显示一些具体的水果名。请问这怎么实现，请大家给点提示！谢谢 问题点数：10、回复次数：4Top
1 楼net_lover（【孟子E章】）回复于 2005-06-03 14:51:07 得分 3
http://www.google.com/search?hl=zh-CN&q=dropdownlist++%E8%81%94%E5%8A%A8&lr=Top
2 楼renyu732（Sysinfo）回复于 2005-06-03 15:22:46 得分 5
<form id="Form1" method="post" runat="server">
<asp:DropDownList id="DropDownList1" runat="server"></asp:DropDownList>
<asp:DropDownList id="DropDownList2" runat="server"></asp:DropDownList>
<SCRIPT LANGUAGE="JavaScript">
<!--
//以XML求取数据
function XmlPost(obj)
{
var svalue = obj.value;
var webFileUrl = "?brc_id=" + svalue;
var result = "";
var xmlHttp = new ActiveXObject("MSXML2.XMLHTTP");
xmlHttp.open("POST", webFileUrl, false);
xmlHttp.send("");
result = xmlHttp.responseText;
if(result != "")
{
document.all("DropDownList2").length=0;
var piArray = result.split(",");
for(var i=0;i<piArray.length;i++)
{
var ary1 = piArray[i].toString().split("|");
//alert(ary1[0].toString());
document.all("DropDownList2").options.add(new Option(ary1[1].toString(),ary1[0].toString()));
}
}
else
{
alert(result);
}
}
//-->
</SCRIPT>
</form>
以下为后台代码:
private System.Data.OleDb.OleDbConnection conn;
private DataTable get_dt(string sql)
{
string connstr = "Provider=MSDAORA.1;Password=aqjc;User ID=aqjc;Data Source=aqjc";
this.conn = new OleDbConnection(connstr);
this.conn.Open();
OleDbCommand myOleDbCommand = new OleDbCommand(sql,this.conn);
OleDbDataAdapter myData = new OleDbDataAdapter(myOleDbCommand);
DataSet myDataset = new DataSet();
try
{
myData.Fill(myDataset);
}
catch(Exception ex)
{
throw ex;
}
this.conn.Close();
return myDataset.Tables[0];
}
private void Page_Load(object sender, System.EventArgs e)
{
string brc_id = this.Request.QueryString["brc_id"];
if(brc_id + "a" != "a")
{
this.down2_bind(brc_id);
}
if(!this.IsPostBack)
{
this.down1_bind();
}
}
/// <summary>
/// 返回第2个下拉框需要的值给xmlhttp
/// </summary>
/// <param name="brc_id"></param>
private void down2_bind(string brc_id)
{
string mystr = "";
string sql = "select brc_id,brc_name from asm_branch where brc_parentid = '" + brc_id + "'";
DataTable mytab = this.get_dt(sql);
if(mytab.Rows.Count != 0)
{
for(int i=0;i<mytab.Rows.Count;i++)
{
mystr += "," + mytab.Rows[i][0].ToString() + "|" + mytab.Rows[i][1].ToString();
}
mystr = mystr.Substring(1);
}
this.Response.Write(mystr);
this.Response.End();
}
/// <summary>
/// 绑定第一个下拉框
/// </summary>
private void down1_bind()
{
string sql = "select brc_id,brc_name from asm_branch where brc_level = '1'";
DataTable mytab = this.get_dt(sql);
this.DropDownList1.DataSource = mytab;
this.DropDownList1.DataValueField = "brc_id";
this.DropDownList1.DataTextField = "brc_name";
this.DropDownList1.DataBind();
this.DropDownList1.Attributes.Add("onchange","XmlPost(this);");
}
//以下是VB脚本
<SCRIPT LANGUAGE="vbScript">
<!--
'以XML求取数据
function XmlPost(obj)
dim svalue
svalue = obj.value
dim webFileUrl
webFileUrl = "?brc_id=" + svalue
dim result
set xmlHttp = CreateObject("Microsoft.XMLHTTP")
call xmlHttp.open("POST", webFileUrl, false)
call xmlHttp.send("")
result = xmlHttp.responseText
set downlist = document.all("DropDownList2")
if result <> "" then
document.all("DropDownList2").length=0
dim piArray ,ary1
piArray = split(result,",")
for i=0 to piArray.length - 1
ary1 = split(piArray(i),"|")
downlist.length = downlist.length + 1
downlist.options(downlist.length-1).text = ary1(1)
downlist.options(downlist.length-1).value = ary1(0)
next
else
alert(result)
end if
end function
//-->
</SCRIPT>
http://www.cnblogs.com/gwazy/archive/2005/05/10/152312.html
function Do_Link_Change(ChangeObj,n,jsVal,jsShow)
{
if (n<0) return ;
var e = eval("document.all."+ChangeObj);
for (var i=e.options.length; i>-1; i--)
e.remove(i);
var show = eval(jsShow+"["+ n+"]"); //得到数组名
var val=eval(jsVal+"["+ n+"]");
if (val.length<1) return;
for (var i=0; i<val.length; i++)
e.options.add(new Option(show[i], val[i]));
}
然后你必须在客户端写对应的js变量，例如
var area_show = new Array();
var area_value = new Array();
var point_show = new Array();
var point_value = new Array();
area_show[0]='广东';
area_value[0]=510000;
point_show[0]=new Array();
point_value[0]=new Array();
area_show[1]='广州';
area_value[1]=510100;
point_show[1]=new Array();
point_value[1]=new Array();
point_show[1][0]='天河';
point_value[1][0]=1;
point_show[1][1]='河南';
point_value[1][1]=1;
point_show[1][2]='火车站';
point_value[1][2]=3;
area_show[2]='深圳';
area_value[2]=510200;
point_show[2]=new Array();
point_value[2]=new Array();
point_show[2][0]='南山';
point_value[2][0]=1;
point_show[2][1]='龙岗';
point_value[2][1]=1;
point_show[2][2]='盐田';
point_value[2][2]=3;
然后再第一个dropdownlist里面写 onchange="Do_Link_Change('npoint',this.selectedIndex,'point_value','point_show')"
"npoint"是第二个dropdownlist的id
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3 楼bxl（bxl）回复于 2005-06-14 10:21:09 得分 0
哎，初学呀，还读不懂上边朋友的代码！惭愧惭愧! 有没有简单一点的做法啊 我用的visual studio .netTop
4 楼liangf（你Q不如我Q）回复于 2005-06-14 10:36:06 得分 2
如果不刷新实现，主要是前端js代码比较多，google能搜出很多来，也可以参考下面这个js的专门网站：
http://www.51js.com/forumdisplay.php?fid=1Top
