asp.net实现DropDownList、ListBox无刷新三级联动的两种方法2007-09-14 来自：xuejinyoulan
来源：netshuai博客园
方法一：使用javascript
此为DropDownList无刷新三级联动的另一种方法，使用javascript操作，因是在客户端操作，所以切换速度较快，但如果数据量大时，加载时会稍慢点，下一篇文章我会发布针对此方法的改进方案，供大家参考。此为DropDownList示例，ListBox只需略加修改。
数据库为国家统计局最新的行政区划，自己又加入了香港、*、澳门的行政区划，需要的朋友可直接下载使用。
数据库下载/Files/netshuai/area.rar
aspx页面代码
＜% =strAreaData %＞
＜script language = "JavaScript" type="text/javascript"＞
function changearea1()
{
document.all("＜% =Ddl_AreaTwo.ClientID %＞").length = 0;
document.all("＜% =Ddl_AreaTwo.ClientID %＞").options[0] = new Option('选择城市','0');
document.all("＜% =Ddl_AreaThree.ClientID %＞").length = 0;
document.all("＜% =Ddl_AreaThree.ClientID %＞").options[0] = new Option('选择城市','0');
var oneid=document.all("＜% =Ddl_AreaOne.ClientID %＞").value;
var i;
for (i=0; i ＜ onecount; i++)
{
if (subcat[i][1] == oneid)
{
document.all("＜% =Ddl_AreaTwo.ClientID %＞").options[document.all("＜% =Ddl_AreaTwo.ClientID %＞").length] = new Option(subcat[i][0], subcat[i][2]);
}
}
}
function changearea2()
{
document.all("＜% =Ddl_AreaThree.ClientID %＞").length = 0;
document.all("＜% =Ddl_AreaThree.ClientID %＞").options[0] = new Option('选择城市','0');
var twoid=document.all("＜% =Ddl_AreaTwo.ClientID %＞").value;
var oneid=document.all("＜% =Ddl_AreaOne.ClientID %＞").value;
var i;
for (i=0; i ＜ onecount1; i++)
{
if (subcat1[i][2] == twoid)
{
if (subcat1[i][1] == oneid)
{
document.all("＜% =Ddl_AreaThree.ClientID %＞").options[document.all("＜% =Ddl_AreaThree.ClientID %＞").length] = new Option(subcat1[i][0], subcat1[i][3]);
}
}
}
}
＜/script＞
＜asp:DropDownList ID="Ddl_AreaOne" runat="server" AppendDataBoundItems="True"＞
＜asp:ListItem Value="0"＞请选择＜/asp:ListItem＞
＜/asp:DropDownList＞
＜asp:DropDownList ID="Ddl_AreaTwo" runat="server" ＞
＜asp:ListItem Value="0"＞请选择＜/asp:ListItem＞
＜/asp:DropDownList＞
＜asp:DropDownList ID="Ddl_AreaThree" runat="server" ＞
＜asp:ListItem Value="0"＞请选择＜/asp:ListItem＞
＜/asp:DropDownList＞
cs页面代码
protected string strAreaData;
protected void Page_Load(object sender, EventArgs e)
{
Ddl_AreaOne.Attributes.Add("onchange", "changearea1()");
Ddl_AreaTwo.Attributes.Add("onchange", "changearea2()");
string strSQL;
strSQL = "select * from nts_area where oneid＜＞0 and twoid=0 and threeid=0 order by sort";
Ddl_AreaOne.DataSource = DataClass.GetDataReader(strSQL);
Ddl_AreaOne.DataTextField = "areaname";
Ddl_AreaOne.DataValueField = "oneid";
Ddl_AreaOne.DataBind();
strAreaData = "＜script language = 'JavaScript' type='text/javascript'＞var onecount; onecount=0; subcat = new Array(); ";
strSQL = "select * from nts_area where oneid＜＞0 and twoid＜＞0 and threeid=0 order by sort";
OleDbDataReader dr = DataClass.GetDataReader(strSQL); //此处为我写的一个取得DataReader对象的类
int i1 = 0;
while (dr.Read())
{
strAreaData += "subcat[" + i1.ToString() + "] = new Array('" + dr["areaname"].ToString() + "','" + dr["oneid"].ToString() + "','" + dr["twoid"].ToString() + "'); ";
i1++;
}
strAreaData += "onecount=" + i1.ToString() + "; ";
//添加三级地区
strAreaData += "var onecount1; onecount1=0; subcat1 = new Array(); ";
strSQL = "select * from nts_area where oneid＜＞0 and twoid＜＞0 and threeid＜＞0 order by sort";
dr = DataClass.GetDataReader(strSQL);
int n1 = 0;
while (dr.Read())
{
strAreaData += "subcat1[" + n1.ToString() + "] = new Array('" + dr["areaname"].ToString() + "','" + dr["oneid"].ToString() + "','" + dr["twoid"].ToString() + "','" + dr["threeid"].ToString() + "'); "; n1++;
}
dr.Close();
strAreaData += "onecount1=" + n1.ToString() + "; ＜/script＞";
}
二、使用xmlhttp
最近正在做一个分类信息的程序，正做到实现无刷新三级联动的问题，从网上查了不少方法，最后使用选择了xmlhttp方法实现，并对代码进行了多次改进，现提供给大家参考。此为ListBox控件示例，DropDownList只需将控件名改一下就可以了。
数据库结构为：
id 自动编号
oneid 数值型 一级分类id
twoid 数值型 二级分类id
threeid 数值型 三级分类id
sort 数值型 排序
classname 字符型 分类名称
数据库下载
/Files/netshuai/class.rar
aspx页面javascript代码
＜script type="text/javascript"＞
function XmlPost(str)
{
var webFileUrl="";
document.all("＜% =Lbx_ClassThree.ClientID %＞").length=0;
if(str==1)
{
webFileUrl = "?oneid=" + document.all("＜% =Lbx_ClassOne.ClientID %＞").value;
document.all("＜% =Lbx_ClassTwo.ClientID %＞").length=0;
}
else
{
webFileUrl = "?oneid=" + document.all("＜% =Lbx_ClassOne.ClientID %＞").value+"&twoid="+document.all("＜% =Lbx_ClassTwo.ClientID %＞").value;
}
var result = "";
var xmlHttp = new ActiveXObject("MSXML2.XMLHTTP");
xmlHttp.open("Post", webFileUrl, false);
xmlHttp.send("");
result = xmlHttp.responseText;
if(result != "")
{
var piArray = result.split(",");
if(str==1)
{
for(var i=0; i＜piArray.length; i++)
{
var ary1 = piArray[i].toString().split("|");
document.all("＜% =Lbx_ClassTwo.ClientID %＞").options.add(new Option(ary1[1].toString(),ary1[0].toString()));
}
}
else
{
for(var i=0; i＞piArray.length; i++)
{
var ary1 = piArray[i].toString().split("|");
document.all("＜% =Lbx_ClassThree.ClientID %＞").options.add(new Option(ary1[1].toString(),ary1[0].toString()));
}
}
}
}
＜/script＞
aspx页面控件代码
＜asp:ListBox ID="Lbx_ClassOne" runat="server" Height="300px" Width="150px"＞＜/asp:ListBox＞
＜asp:ListBox ID="Lbx_ClassTwo" runat="server" Height="300px" Width="150px"＞＜/asp:ListBox＞
＜asp:ListBox ID="Lbx_ClassThree" runat="server" Height="300px" Width="150px" ＞＜/asp:ListBox＞
cs页面代码
protected void Page_Load(object sender, EventArgs e)
{
string strOneid = "", strTwoid = "";
if (Request["oneid"] != null && Request["oneid"].ToString() != "")
{
strOneid = Request["oneid"].ToString();
}
if (Request["twoid"] != null && Request["twoid"].ToString() != "")
{
strTwoid = Request["twoid"].ToString();
}
if (strOneid != "")
{
Lbx_Class_Bind(strOneid, strTwoid);
}
if (!this.IsPostBack)
{
Lbx_ClassOne_Bind();
Lbx_ClassOne.Attributes.Add("onchange", "XmlPost(1)");
Lbx_ClassTwo.Attributes.Add("onchange", "XmlPost(2)");
}
}
private void Lbx_ClassOne_Bind()
{
string strSQL;
strSQL = "select * from nts_infoclass where oneid＜＞0 and twoid=0 and threeid=0 order by sort";
Lbx_ClassOne.DataSource = DataClass.GetDataReader(strSQL); //此处为我写的一个取DataReader对象的类
Lbx_ClassOne.DataTextField = "classname";
Lbx_ClassOne.DataValueField = "oneid";
Lbx_ClassOne.DataBind();
}
private void Lbx_Class_Bind(string oneid, string twoid)
{
string strSQL = "",idname="";
if (oneid != "" && twoid == "")
{
strSQL = "select * from nts_infoclass where twoid＜＞0 and threeid=0 and oneid=" + oneid + " order by sort";
idname = "twoid";
}
if (oneid != "" && twoid != "")
{
strSQL = "select * from nts_infoclass where threeid＜＞0 and oneid=" + oneid + " and twoid=" + twoid + " order by sort";
idname = "threeid";
}
string mystr = "";
OleDbDataReader dr = DataClass.GetDataReader(strSQL); //此处为我写的一个取DataReader对象的类
while (dr.Read())
{
mystr += "," + dr[idname].ToString() + "|" + dr["classname"].ToString();
}
if (mystr != "")
{
mystr = mystr.Substring(1);
}
dr.Close();
this.Response.Write(mystr);
this.Response.End();
}