Question

用ajaxpro实现多级dropdownlist无刷新联动后，获取dropdownlist选中项的值出错

用ajaxpro绑定dropdownlist方法：
[AjaxPro.AjaxMethod]
public DataSet GetCityData(string proid)
{

string getCity = "select * from zd_synthesis t where t.dictionary=100025 and t.pitemid=" + proid;
DataSet ds = jklmAdmin.Helper.DataHelper.ExecuteDataset(getCity);

return ds;
}
JS代码：
function BindToCity(ProvinceID,DDL_City_ID)
{
var DataSet_City = Admin_SPConsult_SPConsult_Applay.GetCityData(ProvinceID).value;//注意加Value
var DDL_City = document.getElementById(DDL_City_ID);
DDL_City.length = 0;//清除已有选项
DDL_City.options.add(new Option("--请选择--",0));
var Length = DataSet_City.Tables[0].Rows.length;
if(Length!=0)
{
for(var i=0;i <Length;i++)
{
var Text = DataSet_City.Tables[0].Rows[i].ITEMNAME;//必须和DataSet的列名一致
var Value = DataSet_City.Tables[0].Rows[i].ITEMID;
DDL_City.options.add(new Option(Text,Value));
}
}
else
{
var DDL_Area = document.getElementById("ddlHp");
DDL_Area.length = 0;
};
return;
}

实现了dropdownlist无刷新多级联动，但是获取dropdownlist值时出错，查看页面源代码发现
<select name="ddlCity" id="ddlCity" onchange="BindToHP(this.options[selectedIndex].value,'ddlHp');">
<option value="-1">--请选择--</option>
</select>市</td>
并没有数据，请问这种情况下怎么获取dropdownlist选中项的值呢？

Answer 1

DDL_City.options.add(new Option(Text,Value));
你在客户端用这种方法增加，当然加不成了
客户端只能新建元素节点
然后appendChild()这样来加