1 Ajax.dll 的应用
2 ajax 函数的实现（1 无法调用服务器控件，如给服务器控件赋值 获取服务器状态等 若需以上操作 通过ajax函数的参数来传值到后台 2 要有返回值 由回调函数来处理 ）。
3 回调函数 ：处理后台返回的值 ，对ajax函数执行的结果进行处理等。
4 用户控件中的服务器控件 后台给定的id在前台无法使用 （设置clienetidmode等方式 或者 <%=ddl1.clientid %>)
5 xml 字符串构造
6 javascript 加载ajax函数返回的结果（xml 字符串） 。
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="area.ascx.cs" Inherits="CControl.userControl.areaControl" %>
<script type="text/javascript">
var str = "";
function SetAreaId(ClassID) {
var hiddenID = document.getElementById("HiddenId");
hiddenID.value = ClassID;
var HiddenText = document.getElementById("HiddenText");
var drp1 = document.getElementById("DropDownList1");
var drp2 = document.getElementById("DropDownList2");
var drp3 = document.getElementById("DropDownList3");
if (drp1.selectedIndex > -1) {
HiddenText.value = drp1.options[drp1.selectedIndex].text;
if (drp2 != null && drp2.selectedIndex > -1) {
HiddenText.value += "-" + drp2.options[drp2.selectedIndex].text;
if (drp3 != null && drp3.selectedIndex > -1) {
HiddenText.value += "-" + drp3.options[drp3.selectedIndex].text;
}
}
}
}
function loadsecond(ClassID) {
//ClassID为接收传递的大类编号
var drp2 = document.getElementById("DropDownList2");
SetAreaId(ClassID);
if (drp2 != null) {
var drp3 = document.getElementById("DropDownList3");
RemoveAll(drp2);
if (drp3 != null)
RemoveAll(drp3);
str = areaControl.bindsecond(ClassID, callbackcomplete);
}
}
function callbackcomplete(res) {
var oDoc = new ActiveXObject("MSXML2.DOMDocument");
oDoc.loadXML(res.value);
items1 = oDoc.selectNodes("/ClassLists/List/name");
items2 = oDoc.selectNodes("/ClassLists/List/id");
var itemsLength = items1.length;
var drp2 = document.getElementById("DropDownList2");
for (i = 0; i < itemsLength; i++) {
var newOption = document.createElement("OPTION");
newOption.text = items1[i].text;
newOption.title = items1[i].text;
newOption.value = items2[i].text;
drp2.options.add(newOption);
}
}
function RemoveAll(oElem) {
//清除DropDownList2的所有项
var i = 0;
if (oElem != null)
for (i = oElem.length; i >= 0; i--) {
oElem.options.remove(i);
} }
function loadthird(ClassID) {
//ClassID为接收传递的大类编号
var drp3 = document.getElementById("DropDownList3");
SetAreaId(ClassID);
if (drp3 != null) {
RemoveAll(drp3);
str = areaControl.Bindthird(ClassID, callbackthirdcomplete);
} }
function callbackthirdcomplete(res) {
var oDoc = new ActiveXObject("MSXML2.DOMDocument");
oDoc.loadXML(res.value);
items1 = oDoc.selectNodes("/ClassLists/List/name");
items2 = oDoc.selectNodes("/ClassLists/List/id"); var itemsLength = items1.length;
var drp3 = document.getElementById("DropDownList3");
for (i = 0; i < itemsLength; i++) {
var newOption = document.createElement("OPTION");
newOption.text = items1[i].text;
newOption.title = items1[i].text;
newOption.value = items2[i].text;
drp3.options.add(newOption);
}
}
</script>
<ul><li><div style="float:left">
省<asp:DropDownList ID="DropDownList1" Width="150px" runat="server" ClientIDMode="Static" οnchange="javascript:loadsecond(this.options[this.selectedIndex].value);"> </asp:DropDownList> </div></li>
<li><div style="float:left">
<asp:Panel runat="server" ID="City" >
市<asp:DropDownList ID="DropDownList2" Width="150px" runat="server" ClientIDMode="Static" οnchange="javascript:loadthird(this.options[this.selectedIndex].value);"> </asp:DropDownList> </asp:Panel> </div></li> <li> <div style="float:left"> <asp:Panel runat="server" ID="Town">
县<asp:DropDownList ID="DropDownList3" Width="150px" runat="server" ClientIDMode="Static" οnchange="javascript:SetAreaId(this.options[this.selectedIndex].value);"> </asp:DropDownList> </asp:Panel> </div> </li> </ul>
<asp:HiddenField ID="HiddenId" ClientIDMode="Static" runat="server" />
<asp:HiddenField ID="HiddenText" ClientIDMode="Static" runat="server" />
后台代码：
namespace CControl.userControl { /// <summary> /// 显示地区列表数量,最多三级,add by clare /// </summary>
public partial class areaControl : System.Web.UI.UserControl { /// <summary>
/// 显示的地区层数 最多3层,默认3层
/// </summary>
public int Floor {
get
{
if (ViewState["_floor"] == null)
return 3;
else
return (int)ViewState["_floor"]; ;
}
set {
if(value>0 && value<4)
ViewState["_floor"] = value;
else
ViewState["_floor"] = 3;
} }
/// <summary> /// 二级是否添加"全部"选择条,默认是 /// </summary>
public bool SecondNeedZero
{
get
{
if (ViewState["_SecondZeroItem"] == null)
return true;
else
return (bool)ViewState["_SecondZeroItem"];
}
set { ViewState["_SecondZeroItem"] = value; }
}
/// <summary> /// 三级是否添加全部选择,默认是 /// </summary>
public bool ThirdNeedZero {
get {
if (ViewState["_thirdNeedZero"] == null)
return true;
else
return (bool)ViewState["_thirdNeedZero"];
}
set { ViewState["_thirdNeedZero"] = value; } }
/// <summary> /// 首级地区从电信端列表里读取,默认false; /// </summary>
public bool FirstFromTelecom {
get {
if (ViewState["_firstFromTelecom"] == null)
return false;
else
return (bool)ViewState["_firstFromTelecom"];
}
set { ViewState["_firstFromTelecom"] = value; }
}
public int GetAreasID {
get {
if (string.IsNullOrEmpty(this.HiddenId.Value))
return 0;
return int.Parse(this.HiddenId.Value); }
}
/// <summary> /// 返回地区名,多级累加的 /// </summary>
public string AreasName
{
get { return this.HiddenText.Value; }
} //private bool _secondFromHotel = false;
/ <summary> / 二级菜单是否从酒店列表里读取,若是,则FirstFromTelecom必须为true / </summary> //public bool SecondFromHotel //{ // get { return _secondFromHotel; } // set { _secondFromHotel = value; } //}
protected void Page_Load(object sender, EventArgs e)
{
Ajax.Utility.RegisterTypeForAjax(typeof(areaControl));
if (!IsPostBack)
{
switch (Floor)
{
case 1: City.Visible = false;
//DropDownList2.Attributes.Add("display", "none");
//DropDownList3.Attributes.Add("display", "none");
Town.Visible = false;
break;
case 2:
Town.Visible = false;
//DropDownList3.Attributes.Add("display", "none");
break;
default :
break;
}
}
bindFirst();
}
protected void bindFirst()
{
DropDownList1.Items.Clear();
if (FirstFromTelecom)
{
PubInfo.BLL.SRC_T_Telcom bll = new PubInfo.BLL.SRC_T_Telcom();
DataSet ds = bll.GetTelcomList();
foreach (DataRow item in ds.Tables[0].Rows)
{
//DropDownList1.DataSource = ds;
//DropDownList1.DataTextField = "Name";
//DropDownList1.DataValueField = "areaId";
//DropDownList1.SelectedIndex = -1;
try {
DropDownList1.Items.Add(new ListItem(item["Name"].ToString(), item["areaId"].ToString()));
} catch { }
}
}
else
{
PubInfo.BLL.Area bll = new PubInfo.BLL.Area();
int total=0; ///这个函数.GetProvince有问题,需要修改
List<PubInfo.Model.Area> models= bll.GetProvinceAreas(0,0,out total);
foreach (PubInfo.Model.Area item in models)
{
DropDownList1.Items.Add(new ListItem(item.AreaName,item.ID.ToString()));
}
}
foreach (ListItem item in DropDownList1.Items)
{
item.Attributes["title"] = item.Text;
}
DropDownList1.Items.Insert(0,new ListItem("请选择...", "-1"));
DropDownList1.SelectedIndex = -1;
}
[Ajax.AjaxMethod]
public string bindsecond(int P)
{
StringBuilder sb = new StringBuilder();
sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
sb.Append("<ClassLists>");
List<PubInfo.Model.Area> areas = new List<PubInfo.Model.Area>();
int total = 0; ///这个调用的函数也是有问题的,没有 处理pageSize=0的情况
areas = new PubInfo.BLL.Area().GetTownAreas(P, 0, 0, out total);
if (SecondNeedZero)
{
sb.AppendFormat("<List><id>{0}</id><name>{1}</name></List>", -1, "请选择...");
}
foreach (PubInfo.Model.Area item in areas)
{
sb.AppendFormat("<List><id>{0}</id><name>{1}</name></List>", item.ID, item.AreaName);
}
sb.Append("</ClassLists>");
return sb.ToString();
}
[Ajax.AjaxMethod]
public string Bindthird(int P)
{
StringBuilder sb = new StringBuilder();
sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
sb.Append("<ClassLists>");
List<PubInfo.Model.Area> areas = new List<PubInfo.Model.Area>();
int total = 0; ///这个调用的函数也是有问题的,没有 处理pageSize=0的情况
areas = new PubInfo.BLL.Area().GetTownAreas(P, 0, 0, out total);
if (ThirdNeedZero)
{
sb.AppendFormat("<List><id>{0}</id><name>{1}</name></List>", -1, "请选择");
}
foreach (PubInfo.Model.Area item in areas)
{
sb.AppendFormat("<List><id>{0}</id><name>{1}</name></List>", item.ID, item.AreaName);
}
sb.Append("</ClassLists>");
return sb.ToString();
}
}
}