利用Asp.Net AJAX的CascadingDropDown控制項結合Web Service來讀取資料

2008-03-16

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ASP.NET AJAX
2008-03-17

這個範例主要是利用Web Service結合AJAX的CascadingDropDown控制項來讀取資料

CascadingDropDown_CS.aspx

01 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="CascadingDropDown_CS.aspx.cs"
02     Inherits="CascadingDropDown_CS" %>
03
04 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
05 <html xmlns="http://www.w3.org/1999/xhtml">
06 <head id="Head1" runat="server">
07     <title>未命名頁面</title>
08 </head>
09 <body>
10     <form id="form1" runat="server">
11         <asp:ScriptManager ID="ScriptManager1" runat="server">
12         </asp:ScriptManager>
13         <asp:DropDownList ID="DropDownList1" runat="server">
14         </asp:DropDownList>
15         <asp:DropDownList ID="DropDownList2" runat="server">
16         </asp:DropDownList>
17         <ajaxtoolkit:cascadingdropdown id="CascadingDropDown1" runat="server" category="ClassA"
18             loadingtext="載入中..." prompttext="請選擇" servicemethod="GetDropDownContentsPageMethod"
19             targetcontrolid="DropDownList1">
20 </ajaxtoolkit:cascadingdropdown>
21         <ajaxtoolkit:cascadingdropdown id="CascadingDropDown2" runat="server" category="ClassB"
22             loadingtext="載入中..." prompttext="請選擇" servicemethod="GetDropDownContentsPageMethod"
23             targetcontrolid="DropDownList2" parentcontrolid="DropDownList1">
24 </ajaxtoolkit:cascadingdropdown>
25     </form>
26 </body>
27 </html>
28

CascadingDropDown_CS.aspx.cs

using System;
02

using System.Data;
03

using System.Configuration;
04

using System.Collections;
05

using System.Web;
06

using System.Web.Security;
07

using System.Web.UI;
08

using System.Web.UI.WebControls;
09

using System.Web.UI.WebControls.WebParts;
10

using System.Web.UI.HtmlControls;
11

using System.Web.Services;
12

using AjaxControlToolkit;
13

public partial class CascadingDropDown_CS : System.Web.UI.Page
15

{
16

protected void Page_Load(object sender, EventArgs e)
17

{
18

}
20

21 [WebMethod]
22

[System.Web.Script.Services.ScriptMethod]
23

public static CascadingDropDownNameValue[] GetDropDownContentsPageMethod(string knownCategoryValues, string category)
24

{
25

return new WebService().GetDropDownContents(knownCategoryValues, category);
26

}
27

}

在App_Code裡加入一個WebService.cs檔
WebService.cs

using System;
02

using System.Web;
03

using System.Collections;
04

using System.Web.Services;
05

using System.Web.Services.Protocols;
06

using AjaxControlToolkit;
07

using System.Collections.Generic;
08

using System.Collections.Specialized;
09

/// <summary>
11

/// WebService 的摘要描述
12

/// </summary>
13

[WebService(Namespace = "http://tempuri.org/")]
14

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
15

public class WebService : System.Web.Services.WebService
16

{
17

18 public WebService()
19

{
20

21 //如果使用設計的元件，請取消註解下行程式碼
22

//InitializeComponent();
23

}
24

25 [WebMethod]
26

public CascadingDropDownNameValue[] GetDropDownContents(string knownCategoryValues, string category)
27

{
28

29 List<CascadingDropDownNameValue> values = new List<CascadingDropDownNameValue>();
30

31 if (category == "ClassA")
32

{
33

values.Add(new CascadingDropDownNameValue("ClassA-1", "1"));
34

values.Add(new CascadingDropDownNameValue("ClassA-2", "2"));
35

values.Add(new CascadingDropDownNameValue("ClassA-3", "3"));
36

}
37

38 if (category == "ClassB")
39

{
40

StringDictionary kv = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);
41

42 int modelId;
43

if (!kv.ContainsKey("ClassA") || !Int32.TryParse(kv["ClassA"], out modelId))
44

{
45

return null;
46

}
47

48 //選擇ClassA的第1個項目
49

if (modelId == 1)
50

{
51

values.Add(new CascadingDropDownNameValue("ClassA-1,ClassB-1", "1"));
52

values.Add(new CascadingDropDownNameValue("ClassA-1,ClassB-2", "2"));
53

values.Add(new CascadingDropDownNameValue("ClassA-1,ClassB-3", "3"));
54

}
55

56 //選擇ClassA的第2個項目
57

if (modelId == 2)
58

{
59

values.Add(new CascadingDropDownNameValue("ClassA-2,ClassB-1", "1"));
60

values.Add(new CascadingDropDownNameValue("ClassA-2,ClassB-2", "2"));
61

values.Add(new CascadingDropDownNameValue("ClassA-2,ClassB-3", "3"));
62

}
63

64 //選擇ClassA的第3個項目
65

if (modelId == 3)
66

{
67

values.Add(new CascadingDropDownNameValue("ClassA-3,ClassB-1", "1"));
68

values.Add(new CascadingDropDownNameValue("ClassA-3,ClassB-2", "2"));
69

values.Add(new CascadingDropDownNameValue("ClassA-3,ClassB-3", "3"));
70

}
71

}
73

74 return values.ToArray();
75

}
76

}

GetDropDownContents方法可以改為兩種方式來讀取資料：
1.利用資料庫
2.利用XML

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