Ajax实现三级联动

Web.Config中：
-----------------------------------------------------------------------------------------------
<httpHandlers>
<add verb="POST,GET" path="ajaxpro/*.ashx" type="AjaxPro.AjaxHandlerFactory, AjaxPro.2"/>
</httpHandlers>
-----------------------------------------------------------------------------------------------
javascript脚本：
----------------------------------------------------------------------------------------------- <script language="javascript" type="text/javascript">
<!--
// ACLOUD 常用JS函数
function getBid(s){
return document.getElementById(s);
}
function getBmc(s){
return document.getElementByName(s);
}
//显示分类列表// key,stid,tb,bskeyid,bsid
function showNext(obj,key,id,tb,bskeyid,bsidv)
{
if(bsidv==null || bsidv=="" || bsidv.length<1)return;
var slt =getBid(obj);
var v = AddPro.getNextClass(key,id,tb,bskeyid,bsidv).value; // 类的名称
//alert(v);
//return;
if (v != null){
if(v != null && typeof(v) == "object" && v.Tables != null)
{
slt.length = 0;
slt.options.length = 0;
slt.options.add(new Option("请选择",0));
//加了个“请选择”主要为了触发onchange事件
if(obj=="ddl2"){
getBid("ddl3").options.length=0;
getBid("ddl3").options.add(new Option("请选择",0));
}
for(var i=0; i<v.Tables[0].Rows.length; i++)
{
var txt = v.Tables[0].Rows[i].txt; //这个地方需要注意区分大小写
var vol = v.Tables[0].Rows[i].vol; //跟dataset表的列名称要一
致
slt.options.add(new Option(txt,vol));
}
}
}
return;
}
//JS方法取值
function getData(){
var str = getBid("ddl1").value +":"+ getBid("ddl2").value +":"+ getBid("ddl3").value;
str = "您选择的是：" +str;
getBid("<%=Label1.ClientID%>").innerText = str;
alert(str);
return false;
}
-->
</script>
----------------------------------------------------后台----------------------------------------------------------- Page_Load中：
//必要的
AjaxPro.Utility.RegisterTypeForAjax(typeof(AddPro));
----------------------------------------------------后台--------------------------------------------------------- [AjaxPro.AjaxMethod]
public DataSet getNextClass(string key, string stid, string tb, string bskeyid, string bsid) {
//因为不希望页面可以知道字段名称所以as txt,id as vol 如果是sql ser 可以用=
//页面获取的列名称必须跟这个一同样而且区分大小写一般都是这个地方容易疏忽了
//所以二级分类没变化
try
{
return BLL_Production.ToGetst(key,stid,tb,bskeyid,bsid);
}
catch
{
//throw;
return null;
}
}
private void BindDc()
{
//第一个
ddl1.DataSource = BLL_ProBigClass.GetBigClassModel();
ddl1.DataTextField = "Pro_BigClass1";
ddl1.DataValueField = "ID1";
ddl1.DataBind(); // key,stid,tb,bskeyid,bsid
if (ddl1.DataSource != null) ddl1.Attributes.Add("onchange", "showNext('ddl2','Pro_SmallClass','ID','Tb_Pro_SmallClass','Pro_BigClassID',this.options[selecte dIndex].value);");
//可以先判断DropDownList.SelectedItem.Value
//第二个
ddl2.DataSource = BLL_ProSmallClass.GetSmallClassByID(Convert.ToInt32(ddl1.SelectedItem.Value));
ddl2.DataTextField = "Pro_SmallClass1";
ddl2.DataValueField = "ID1";
ddl2.DataBind();
if (ddl2.DataSource != null) ddl2.Attributes.Add("onchange", "showNext('ddl3','Pro_ThreeClass','ID','Tb_Pro_ThreeClass','Pro_SmallID',this.options[selectedIn dex].value);");
//第三个
ddl3.DataSource = BLL_ProThreeClass.GetThreeClassByID(Convert.ToInt32(ddl2.SelectedItem.Value));
ddl3.DataTextField = "Pro_ThreeClass1";
ddl3.DataValueField = "ID1";
ddl3.DataBind();
}
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