本文將介紹使用 SqlDataSource 更新 GridView 中的資料時，該如何取到使用者於 TemplateField 中控制項的屬性值。
當您使用下列 T-SQL 更新資料時，SqlDataSource 會幫您自動建立 UpdateParameter（如下圖以及下面的程式碼第37-40列）。
1: UPDATE Region
2: SET RegionDescription = @RegionDesc
3: WHERE (RegionID = @RegionID)
程式碼如下：
1: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="SqlDataSourceDemo.aspx.cs" Inherits="WebApplication1.SqlDataSourceDemo" %>
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:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
13: DataKeyNames="RegionID" DataSourceID="SqlDataSource1">
14: <Columns>
15: <asp:BoundField DataField="RegionID" HeaderText="RegionID" ReadOnly="True"
16: SortExpression="RegionID" />
17: <asp:TemplateField HeaderText="RegionDescription"
18: SortExpression="RegionDescription">
19: <ItemTemplate>
20: <asp:Label ID="Label1" runat="server" Text='<%# Bind("RegionDescription") %>'></asp:Label>
21: </ItemTemplate>
22: <EditItemTemplate>
23: <asp:TextBox ID="TextBox1" runat="server"
24: Text='<%# Bind("RegionDescription") %>'></asp:TextBox>
25: </EditItemTemplate>
26: </asp:TemplateField>
27: <asp:CommandField ShowEditButton="True" />
28: </Columns>
29: <EmptyDataTemplate>
30: No Data.
31: </EmptyDataTemplate>
32: </asp:GridView>
33: <asp:SqlDataSource ID="SqlDataSource1" runat="server"
34: ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
35: SelectCommand="SELECT RegionID, RegionDescription FROM Region"
36: UpdateCommand="UPDATE Region SET RegionDescription = @RegionDesc WHERE (RegionID = @RegionID)">
37: <UpdateParameters>
38: <asp:Parameter Name="RegionDesc" />
39: <asp:ControlParameter ControlID="GridView1" Name="RegionID" PropertyName="SelectedValue" />
40: </UpdateParameters>
41: </asp:SqlDataSource>
42: </div>
43: </form>
44: </body>
45: </html>
您可以指定 UpdateParameter 的來源可以是繼承 System.Web.UI.WebControls.Parameter 的類別（例如ControlParameter、SessionParameter等），以 ControlParameter 為例，您可以設定 UpdateParameter 的值是來自於某一控制項的某個屬性，例如上圖 RegionID 參數的值是來自GridView1.SelectedValue。
假設 RegionDesc 參數是要來自於 GridView 控制項中的 TemplateField 裡的 TextBox1.Text（上述程式碼第23-24列），你會發現選不到 GridView 中的控制項。
若自己手動把下列程式碼：
<asp:Parameter Name="RegionDesc" />
改為：
<asp:ControlParameter ControlID="TextBox1" Name="RegionDesc" PropertyName="Text" />
執行更新時會收到找不到控制項的錯誤訊息（如下圖）：
解決方法如下：
- 以本文的程式碼為例，刪除 UpdateParameter 中的 RegionDesc 參數。
-
將 UpdateCommand 中的 RegionDesc 參數名稱改為與欄位名稱相同（下列程式碼的第4列改為第9列的樣子）。
1: <%--<asp:SqlDataSource ID="SqlDataSource1" runat="server"
2: ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
3: SelectCommand="SELECT RegionID, RegionDescription FROM Region"4: UpdateCommand="UPDATE Region SET RegionDescription = @RegionDesc WHERE (RegionID = @RegionID)">--%>
5:6: <asp:SqlDataSource ID="SqlDataSource1" runat="server"
7: ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
8: SelectCommand="SELECT RegionID, RegionDescription FROM Region"
9: UpdateCommand="UPDATE Region SET RegionDescription = @RegionDescription WHERE (RegionID = @RegionID)">
-
所要修改的欄位，對應到的控制項屬性是使用支援讀/寫的資料繫結運算式 Bind。
1: <asp:TextBox ID="TextBox1" runat="server"
2: Text='<%# Bind("RegionDescription") %>'></asp:TextBox>
修改後的完整程式碼如下：
1: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="SqlDataSourceDemo.aspx.cs" Inherits="WebApplication1.SqlDataSourceDemo" %>
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:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
13: DataKeyNames="RegionID" DataSourceID="SqlDataSource1">
14: <Columns>
15: <asp:BoundField DataField="RegionID" HeaderText="RegionID" ReadOnly="True"
16: SortExpression="RegionID" />
17: <asp:TemplateField HeaderText="RegionDescription"
18: SortExpression="RegionDescription">
19: <ItemTemplate>
20: <asp:Label ID="Label1" runat="server" Text='<%# Bind("RegionDescription") %>'></asp:Label>
21: </ItemTemplate>
22: <EditItemTemplate>
23: <asp:TextBox ID="TextBox1" runat="server"
24: Text='<%# Bind("RegionDescription") %>'></asp:TextBox>
25: </EditItemTemplate>
26: </asp:TemplateField>
27: <asp:CommandField ShowEditButton="True" />
28: </Columns>
29: <EmptyDataTemplate>
30: No Data.
31: </EmptyDataTemplate>
32: </asp:GridView>
33: <%--<asp:SqlDataSource ID="SqlDataSource1" runat="server"
34: ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
35: SelectCommand="SELECT RegionID, RegionDescription FROM Region"
36: UpdateCommand="UPDATE Region SET RegionDescription = @RegionDesc WHERE (RegionID = @RegionID)">--%>
37: <asp:SqlDataSource ID="SqlDataSource1" runat="server"
38: ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
39: SelectCommand="SELECT RegionID, RegionDescription FROM Region"
40: UpdateCommand="UPDATE Region SET RegionDescription = @RegionDescription WHERE (RegionID = @RegionID)">
41: <UpdateParameters>
42: <%--<asp:ControlParameter ControlID="TextBox1" Name="RegionDesc" PropertyName="Text" />--%>
43: <asp:ControlParameter ControlID="GridView1" Name="RegionID" PropertyName="SelectedValue" />
44: </UpdateParameters>
45: </asp:SqlDataSource>
46: </div>
47: </form>
48: </body>
49: </html>
【參考資料】
