AJAX Toolkit(2)--CascadeDropDown

使用的数据库是SQL Server 2000的自带示例数据库Northwind，首先在一个下拉列表里面显示左右顾客（Customer），选择了相应的Customer后，显示该Customer的所有合同
首先，ASP.NET页面的组织：

xml 代码

<form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        <!----></asp:ScriptManager>

    <!---->div>
        <asp:DropDownList ID="DropDownList1" runat="server">
        <!----></asp:DropDownList> <!---->
        <asp:DropDownList ID="DropDownList2" runat="server">
        <!----></asp:DropDownList><!---->
        <ajaxToolkit:CascadingDropDown ID="CascadingDropDown1" runat="server" TargetControlID="DropDownList1"
            Category="Customer"  PromptText="Please select a Customers"  LoadingText="[Loading Customers...]"
            ServicePath="WebService.asmx" ServiceMethod="GetCustomers" />
            <!---->
        <ajaxToolkit:CascadingDropDown ID="CascadingDropDown2" runat="server" TargetControlID="DropDownList2"
            Category="Order" PromptText="Please select a order" LoadingText="[Loading orders...]"
            ServiceMethod="GetOrders" ParentControlID="DropDownList1" ServicePath="WebService.asmx" />
        <!---->

    </form>

这里需要注意的是，需要设置第二个的CascadeDropDown的ParentControlID属性为父类的DropdownList ,如ParentControlID="DropDownList1"
下面建立一个WebService：
asmx文件

xml 代码

<%@ WebService Language="C#" CodeBehind="~/App_Code/WebService.cs" Class="WebService" %>

WebService.cs文件

c# 代码

using System;
using System.Web;
using System.Collections.Generic;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.Collections.Specialized;


/// <summary></summary>
/// WebService 的摘要说明
///
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService]
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();
    }

    [WebMethod]
    [System.Web.Script.Services.ScriptMethod]
    public AjaxControlToolkit.CascadingDropDownNameValue[] GetCustomers(string knownCategoryValues, string category)
    {
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["my"].ConnectionString);
        SqlCommand cm = cn.CreateCommand(); //Customer是顶级目录，所以不需要有参数
        cm.CommandText = "select customerID,CompanyName from customers";
        cn.Open();
        SqlDataReader sdr = cm.ExecuteReader();
        List<ajaxcontroltoolkit.cascadingdropdownnamevalue> list = new List<ajaxcontroltoolkit.cascadingdropdownnamevalue>();  </ajaxcontroltoolkit.cascadingdropdownnamevalue></ajaxcontroltoolkit.cascadingdropdownnamevalue>
        while (sdr.Read())
        {
            list.Add(new AjaxControlToolkit.CascadingDropDownNameValue(sdr.GetString(1),sdr.GetString(0)));
        }
        return list.ToArray();

    }
    [WebMethod]
    [System.Web.Script.Services.ScriptMethod]
    public AjaxControlToolkit.CascadingDropDownNameValue[] GetOrders(string knownCategoryValues, string category)
    {
       //解析上一级的选择，注意是上一级Customer下拉列表中的Category属性
       StringDictionary kv = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
        string customer = "";
        if (!kv.ContainsKey("Customer"))
        {
            return null;
        }
        customer = kv["Customer"];
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["my"].ConnectionString);
        SqlCommand cm = cn.CreateCommand();
        cm.CommandText = "select OrderID,OrderDate from orders where CustomerID='" + customer + "'";
        cn.Open();
        SqlDataReader sdr = cm.ExecuteReader();
        List<ajaxcontroltoolkit.cascadingdropdownnamevalue> list = new List<ajaxcontroltoolkit.cascadingdropdownnamevalue>();  </ajaxcontroltoolkit.cascadingdropdownnamevalue></ajaxcontroltoolkit.cascadingdropdownnamevalue>
        while (sdr.Read())
        {
            list.Add(new AjaxControlToolkit.CascadingDropDownNameValue(sdr.GetInt32(0).ToString() + sdr.GetDateTime(1).ToString(), sdr.GetInt32(0).ToString()));
        }
        return list.ToArray();

    }

}

运行结果：

评论

1 楼 hqsss123 2008-03-10  

不错，学习