添加一个 WebService.asmx

添加标签:[System.Web.Script]

Get

{

       Lock(objectLock)//在lock里是一个临界区,在这个临界区只能有一个线程,要有其它线程调用必须等这个线程释放才可以.由 private static XmlDocument xmlDoc;进行线程程操作

{

              xmlDoc.Load(HttpContext.Current.Server.MapPath(“~/App_Data/XML.xml”)// 加载文件

}

return xmlDoc;

}

public static string[] Hierarch//用于返回交节点和子节点//

{

              get{return  new string[] {“province”,”city”};}

}

public AjaxControlToolkit.CascadingDropDownNameValue[] GetDropDownContents(string knowCategoryValues ,string category)

//province name=”江苏,values值就是江苏,category 就是province

{//StringDictionary需要using System.Collections.Specialized

       StringDictionary knownCataegoryValuesDictionary = AjaxControlToolkit.CascadingDropDown.ParaseKnowCategoryValuesString(knowCategoryValues);//将value值转换成StringDictionary类的一个

}

三个 DropDownList

中的 CascadingDropDown1,2,3(CascadingDropDown)

Category:对应着的1,2,3分别填 province,city,county

LoadingText:正在加载

ParentControlID:第一个 CascadingDropDown1不用写,这里实现一个连动效果,当选择省的时候,第二个就会出现相应的市,第三个出现县

       所以第二个与第三个分别选择 DropDownList1,DropDownList2

PromptText 分别真请选择省,请选择市,请选择县

ServiceMethod:都填写 GetDropDownContents

ServicePath:都填写  WebService.asmx

更 UpdatePanel 属性的 Triggers(Collection)添加,更改 ControlID为DropDownList3,EventName 为 SelectedIndexChange 这个是触发事件

UpdatePanel1 的 RenderMode 更改为 Inline 是内嵌式的,UpdateMode 选择 Conditional

 编写 DropDownList3_SelectedIndexChanged(object sender,EventArgs e)

在 Deault.aspx 中的第一个<>中加入 EnableEventValidation=”false”否则 Lable1 会出错,而且还要修改第三 DropDownList 选择它的小三角 AutoPostPack 画勾

代码如下 :

Default.aspx.cs

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

    }

    protected void DropDownList3_SelectedIndexChanged(object sender, EventArgs e)

    {

        if (DropDownList3.SelectedItem.Text == "")

        {

            this.Label1.Text = "您还有一项没有选择哦!";

        }

        else

        {

           Label1.Text = "您的籍贯是" + DropDownList1.SelectedItem.Text+ DropDownList2.SelectedItem.Text + DropDownList3.SelectedItem.Text;

        }

    }

}

WebService.cs

using System;

using System.Web;

using System.Collections.Specialized;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Xml;

/// <summary>

/// WebService 的摘要说明

/// </summary>

[WebService(Namespace = "http://tempuri.org/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

[System.Web.Script.Services.ScriptService]//添加标签,从客户端调用服务端 WebService 方法时

public class WebService : System.Web.Services.WebService

{

    public WebService()

    {

        //如果使用设计的组件，请取消注释以下行

        //InitializeComponent();

    }

    private static XmlDocument xmlDoc;

    private static object objectLock = new object();

    public static XmlDocument Document

    {

        get

        {

            lock (objectLock)//在 lock 里是一个临界区,在这个临界区只能有一个线程,要有其它线程调用必须等这个线程释放才可以.由 private static XmlDocument xmlDoc;进行线程程操作

            {

                if (xmlDoc == null)

                {

                    xmlDoc = new XmlDocument();

                    xmlDoc.Load(HttpContext.Current.Server.MapPath("~/App_Data/XML.xml"));// 加载文件

                }

            }

            return xmlDoc;

        }

    }

    public static string[] Hierarchy

    {

        get { return new string[] { "province", "city" }; } //用于返回交节点和子节点

    }

    [WebMethod]

    public AjaxControlToolkit.CascadingDropDownNameValue[] GetDropDownContents(string knownCategoryValues, string category)

    //province name=江苏,values 值就是江苏,category 就是 province

    {

        //StringDictionary 需要 using System.Collections.Speciallized

        StringDictionary knownCategoryValuesDictionary = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);//将 value 值转换成 StringDictionary 类的一个

        return AjaxControlToolkit.CascadingDropDown.QuerySimpleCascadingDropDownDocument(Document, Hierarchy, knownCategoryValuesDictionary, category);//返回 XML 上的信息显示到界面上来

    }

}

XML.xml

<?xml version="1.0" encoding="utf-8"?>

<WebServer>

  <!--根节点 -->

  <province name="江苏"><!—也可以通过单击右键 查看数据风格 打开一个表进行数据添加 -->

    <city name="盐城市">

      <country name="建湖县" />

      <country name="盐城县" />

    </city>

    <city name="南通市">

      <country name="海安县" />

      <country name="如东县" />

    </city>

    <city name="扬州市">

      <country name="宝应县" />

    </city>

  </province>

  <province name="广东省">

    <city name="潮州市">

      <country name="潮安县">

      </country>

    </city>

    <city name="河源市">

      <country name="东源县">

      </country>

    </city>

  </province>

</WebServer>

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"

Inherits="_Default" EnableEventValidation="False"  %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title>Untitled Page</title>

</head>

<body style="text-align: center">

    <form id="form1" runat="server">

        <asp:ScriptManager ID="ScriptManager1" runat="server" />

        <table border="1">

            <tr>

                <td style="width: 100px">

                    省</td>

                <td style="width: 100px">

                    <asp:DropDownList ID="DropDownList1" runat="server" Width="100px">

                    </asp:DropDownList></td>

            </tr>

            <tr>

                <td style="width: 100px">

                    市</td>

                <td style="width: 100px">

                    <asp:DropDownList ID="DropDownList2" runat="server" Width="100px">

                    </asp:DropDownList></td>

            </tr>

            <tr>

                <td style="width: 100px">

                    县</td>

                <td style="width: 100px">

                    <asp:DropDownList ID="DropDownList3" runat="server" Width="100px"

OnSelectedIndexChanged="DropDownList3_SelectedIndexChanged" AutoPostBack="True">

                    </asp:DropDownList></td>

            </tr>

        </table>

        <div>

            <cc1:CascadingDropDown ID="CascadingDropDown1" runat="server"

TargetControlID="DropDownList1" Category="province" LoadingText="正在加载...."

PromptText="请选择省份" ServiceMethod="GetDropDownContents"  ServicePath="WebService.asmx">

            </cc1:CascadingDropDown>

        </div>

        <cc1:CascadingDropDown ID="CascadingDropDown2" runat="server"

TargetControlID="DropDownList2" Category="city" ParentControlID="DropDownList1"

PromptText="请选择城市" ServiceMethod="GetDropDownContents" ServicePath="WebService.asmx" LoadingText="正在加载....">

        </cc1:CascadingDropDown>

        <cc1:CascadingDropDown ID="CascadingDropDown3" runat="server"

TargetControlID="DropDownList3" Category="country"

ParentControlID="DropDownList2" PromptText="请选择县"

ServiceMethod="GetDropDownContents" ServicePath="WebService.asmx" LoadingText="正在加载...">

        </cc1:CascadingDropDown>

        <asp:UpdatePanel ID="UpdatePanel1" runat="server" RenderMode="Inline" UpdateMode="Conditional">

            <ContentTemplate>

                <asp:Label ID="Label1" runat="server" Text="还未选择"></asp:Label>

            </ContentTemplate>

            <Triggers>

                <asp:AsyncPostBackTrigger ControlID="DropDownList3" EventName="SelectedIndexChanged" />

            </Triggers>

        </asp:UpdatePanel>

    </form>

</body>

</html>