DetailsView中的DropDownList如何與另一DropDownList連動
今天在論壇上看到有討論如何讓DetailsView中的DropDownList互動，平常比較少用DetailsView順便藉機練習一下，說明如下：
- 以下程式碼示範本文網頁的配置：
1: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="DVDemo.aspx.cs" Inherits="WebApplication1.DVDemo" %>2:3: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">4:5: <html xmlns="http://www.w3.org/1999/xhtml">6: <head runat="server">7: <title></title>8: </head>9: <body>10: <form id="form1" runat="server">11: <div>12: <asp:detailsview ID="Detailsview1" runat="server" height="50px" width="125px"13: AutoGenerateRows="False" onitemcommand="Detailsview1_ItemCommand"14: onmodechanging="Detailsview1_ModeChanging" AllowPaging="True"15: DataKeyNames="RegionID" onpageindexchanging="Detailsview1_PageIndexChanging" >16: <Fields>17: <asp:BoundField DataField="RegionId" HeaderText="RegionId" ReadOnly="True" />18: <asp:TemplateField HeaderText="RegionDescription">19: <EditItemTemplate>20: <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("RegionDescription") %>'></asp:TextBox>21: <asp:DropDownList ID="DropDownList1" AutoPostBack="true" runat="server"22: onselectedindexchanged="DropDownList1_SelectedIndexChanged">23: </asp:DropDownList>24: <asp:DropDownList ID="DropDownList2" runat="server">25: </asp:DropDownList>26: </EditItemTemplate>27: <InsertItemTemplate>28: <asp:TextBox ID="TextBox1" runat="server"29: Text='<%# Bind("RegionDescription") %>'></asp:TextBox>30: </InsertItemTemplate>31: <ItemTemplate>32: <asp:Label ID="Label1" runat="server" Text='<%# Bind("RegionDescription") %>'></asp:Label>33: </ItemTemplate>34: </asp:TemplateField>35: <asp:TemplateField HeaderText="Edit">36: <ItemTemplate>37: <asp:Button ID="Button1" runat="server" Text="Edit" CommandName="Edit" />38: </ItemTemplate>39: </asp:TemplateField>40: </Fields>41: </asp:detailsview>42: <br />43: <asp:Button ID="Button2" runat="server" Text="Save" onclick="Button2_Click" />44: </div>45: </form>46: </body>47: </html>
【程式碼說明】
筆者於DetailsView的ReadOnly模式中透過Button1的CommandName來觸發DetailsView的ItemCommand事件，再於事件中以DetailsView的ChangeMode方法來觸發DetailsView的ModeChanging事件。
- 以下程式碼示範當使用者按下Edit按鈕時，觸發ItemCommand事件所進行的動作：
1: protected void Detailsview1_ItemCommand(object sender, DetailsViewCommandEventArgs e)2: {3: if (e.CommandName == "Edit")4: {5: Detailsview1.ChangeMode(DetailsViewMode.Edit);6: DVBind();7: }8: }
- 上述程式碼的DetailsView.ChangeMode方法會觸發ModeChanging事件，程式碼如下：
1: protected void Detailsview1_ModeChanging(object sender, DetailsViewModeEventArgs e)2: {3: if (Detailsview1.CurrentMode == DetailsViewMode.Edit)4: {5: using (NorthwindEntities context = new NorthwindEntities())6: {7: DropDownList ddl1 = Detailsview1.FindControl("DropDownList1") as DropDownList;8: if (ddl1 != null)9: {10: ddl1.DataSource = from p in context.Categories11: select p;12: ddl1.DataTextField = "CategoryName";13: ddl1.DataValueField = "CategoryID";14: ddl1.DataBind();15: ddl1.Items.Insert(0, new ListItem("---", string.Empty));16: }17: }18: }19: }
- 由於DropDownList1的AutoPostBack設定為True，因此當使用者改變選項時，將觸發DropDownList1_SelectedIndexChanged，程式碼如下：
1: protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)2: {3: DropDownList ddl1 = sender as DropDownList;4: if (!string.IsNullOrEmpty(ddl1.SelectedValue))5: {6: DropDownList ddl2 = Detailsview1.FindControl("DropDownList2") as DropDownList;7: if (ddl2 != null)8: {9: using (NorthwindEntities context = new NorthwindEntities())10: {11: int CategoryID = int.Parse(ddl1.SelectedValue);12: ddl2.DataSource = from p in context.Products13: where p.CategoryID == CategoryID14: select p;15: ddl2.DataTextField = "ProductName";16: ddl2.DataValueField = "ProductID";17: ddl2.DataBind();18: }19: }20: }21: }
【完整程式碼】
1: using System;
2: using System.Collections.Generic;
3: using System.Linq;
4: using System.Web;
5: using System.Web.UI;
6: using System.Web.UI.WebControls;
7:
8: namespace WebApplication1
9: {
10: public partial class DVDemo : System.Web.UI.Page
11: {
12: protected void Page_Load(object sender, EventArgs e)
13: {
14: if (!IsPostBack) DVBind();
15: }
16:
17: private void DVBind()
18: {
19: using (NorthwindEntities context = new NorthwindEntities())
20: {
21: Detailsview1.DataSource = from p in context.Regions
22: select p;
23: Detailsview1.DataBind();
24:
25: }
26: }
27:
28: protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
29: {
30: DropDownList ddl1 = sender as DropDownList;
31: if (!string.IsNullOrEmpty(ddl1.SelectedValue))
32: {
33: DropDownList ddl2 = Detailsview1.FindControl("DropDownList2") as DropDownList;
34: if (ddl2 != null)
35: {
36: using (NorthwindEntities context = new NorthwindEntities())
37: {
38: int CategoryID = int.Parse(ddl1.SelectedValue);
39: ddl2.DataSource = from p in context.Products
40: where p.CategoryID == CategoryID
41: select p;
42: ddl2.DataTextField = "ProductName";
43: ddl2.DataValueField = "ProductID";
44: ddl2.DataBind();
45: }
46: }
47: }
48: }
49:
50: protected void Detailsview1_ModeChanging(object sender, DetailsViewModeEventArgs e)
51: {
52: if (Detailsview1.CurrentMode == DetailsViewMode.Edit)
53: {
54: using (NorthwindEntities context = new NorthwindEntities())
55: {
56: DropDownList ddl1 = Detailsview1.FindControl("DropDownList1") as DropDownList;
57: if (ddl1 != null)
58: {
59: ddl1.DataSource = from p in context.Categories
60: select p;
61: ddl1.DataTextField = "CategoryName";
62: ddl1.DataValueField = "CategoryID";
63: ddl1.DataBind();
64: ddl1.Items.Insert(0, new ListItem("---", string.Empty));
65: }
66: }
67: }
68: }
69:
70: protected void Detailsview1_ItemCommand(object sender, DetailsViewCommandEventArgs e)
71: {
72: if (e.CommandName == "Edit")
73: {
74: Detailsview1.ChangeMode(DetailsViewMode.Edit);
75: DVBind();
76: }
77: }
78:
79: protected void Button2_Click(object sender, EventArgs e)
80: {
81: string RegionID = string.Empty;
82: string RegionDescription = string.Empty;
83: string CategoryID = string.Empty;
84: string ProductID = string.Empty;
85:
86: if (Detailsview1.CurrentMode == DetailsViewMode.Edit)
87: {
88: RegionID = Detailsview1.DataKey[0].ToString();
89: TextBox txtRegionDesc = Detailsview1.FindControl("TextBox1") as TextBox;
90: if (txtRegionDesc != null) RegionDescription = txtRegionDesc.Text;
91: DropDownList ddl1 = Detailsview1.FindControl("DropDownList1") as DropDownList;
92: if (ddl1 != null) CategoryID = ddl1.SelectedValue;
93: DropDownList ddl2 = Detailsview1.FindControl("DropDownList2") as DropDownList;
94: if (ddl2 != null) ProductID = ddl2.SelectedValue;
95: }
96:
97: Response.Write(string.Format("{0},{1},{2},{3}", RegionID, RegionDescription, CategoryID, ProductID));
98: }
99:
100: protected void Detailsview1_PageIndexChanging(object sender, DetailsViewPageEventArgs e)
101: {
102: Detailsview1.ChangeMode(DetailsViewMode.ReadOnly);
103: Detailsview1.PageIndex = e.NewPageIndex;
104: DVBind();
105: }
106: }
107: }