使用AjaxPro

protected void Page_Load(object sender, EventArgs e)
{
AjaxPro.Utility.RegisterTypeForAjax(typeof(SelectRoomByCommunity));
}

/// <summary>
/// 查询置顶小区
/// </summary>
/// <returns></returns>
[AjaxPro.AjaxMethod]
public List<RoomByCommunity> GetTopRoom(string co_autoid)
{
List<RoomByCommunity> lis = new List<RoomByCommunity>();
lis = new RoomService().GetTopRoom(co_autoid);

return lis;
}

//获取下一级Room
function GetNextRom(RBC_AutoID) {
$("#input_Return_SelectCommunity").show();
var x = CRM.Page.crm.UserContronel.SelectRoomByCommunity.GetNextRoom(RBC_AutoID);
$("#AreaList_SelectRoomByCommunity").html("")
$(x.value).each(function(index, ele) {
if (ele.RBC_IsLast == 1) {//最后一级
var topcom = '<a   onClick=GetRoomAddress("' + ele.RBC_AutoID + '","' + ele.RBC_Name + '")>' + ele.RBC_Name + '</a>';
} else {
var topcom = '<a   onClick=GetNextRom("' + ele.RBC_AutoID + '")>' + ele.RBC_Name + '</a>';
}
$("#AreaList_SelectRoomByCommunity").html($("#AreaList_SelectRoomByCommunity").html() + topcom);
});
$("#AreaList_SelectRoomByCommunity").html($("#AreaList_SelectRoomByCommunity").html() + '<div class="clear"></div>');
}

<httpHandlers>
<add verb="POST,GET" path="ajaxpro/*.ashx" type="AjaxPro.AjaxHandlerFactory,AjaxPro.2"/>
</httpHandlers>