Abstract
在.NET 1.x的DataGrid，可以在ItemCommand event的e.Item.ItemIndex獲得目前的RowIndex，但在.NET 2.0的GridView，卻無法使用這種方式在RowCommand event獲得RowIndex。
Motivation
為什麼需要在RowCommand event獲得RowIndex呢?通常一個Table的PK或FK並不會顯示在GridView上，而會設定在DataKeyNames property，然後再RowCommand event根據RowIndex讀出該row的PK或FK，所以第一步，必須先能在RowCommand獲得目前的RowIndex。
Introduction
.NET 1.x DataGrid
在.NET 1.x的DataGrid，若要使用LinkButton，一樣得放在TemplateColumn內，且ItemCommand event的e.Item.ItemIndex就可抓到RowIndex。
當在DataGrid點下FirstName後，會在下方的Label顯示LastName，LastName是此例的DataKey。
1
<%@ Import Namespace="System.Data" %>
2<%@ Import Namespace="System.Data.SqlClient" %>
3
4<%@ Page Language="C#" %>
5
6<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
7
8<script runat="server">
9
/*
10
(C) OOMusou 2007 http://oomusou.cnblogs.com
11
12Filename : DataGrid_DataKeyField.aspx
13Compiler : Visual Studio 2005 / C# 2.0 / ASP.NET 2.0
14Description : Demo how to get RowIndex in DataGrid's LinkButton
15Release : 06/26/2007 1.0
16
*/
17 protected void Page_Load(object sender, EventArgs e) {
18 if (!IsPostBack)
19 DataGrid1_DataBind();
20 }
21
22 protected void DataGrid1_DataBind() {
23 string strSQL = "SELECT TOP 10 " +
24 "fname," +
25 "lname " +
26 "FROM employee";
27 SqlConnection con = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=pubs;Integrated Security=True");
28 SqlDataAdapter da = new SqlDataAdapter(strSQL, con);
29 DataSet ds = new DataSet();
30
31 try {
32 da.Fill(ds);
33 }
34 catch (Exception err) {
35 Response.Write(err.ToString());
36 return;
37 }
38 finally {
39 if ((con != null) && (con.State == ConnectionState.Open))
40 con.Close();
41 }
42
43 DataGrid1.DataSource = ds;
44 DataGrid1.DataKeyField = "lname";
45 DataGrid1.AutoGenerateColumns = false;
46 DataGrid1.DataBind();
47 }
48
49 protected void DataGrid1_ItemCommand(object source, DataGridCommandEventArgs e) {
50 if (e.CommandName == "Select")
51 Label1.Text = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
52
}
53</script>
54
55<html xmlns="http://www.w3.org/1999/xhtml">
56<head runat="server">
57 <title>Untitled Page</title>
58</head>
59<body>
60 <form id="form1" runat="server">
61 <asp:DataGrid ID="DataGrid1" runat="server" OnItemCommand="DataGrid1_ItemCommand">
62 <Columns>
63 <asp:TemplateColumn HeaderText="First Name">
64 <ItemTemplate>
65 <asp:LinkButton ID="LinkButton1" runat="server" CommandName="Select" Text='<%#DataBinder.Eval(Container.DataItem,"fname")%>'>
66 </asp:LinkButton>
67 </ItemTemplate>
68 </asp:TemplateColumn>
69 </Columns>
70 </asp:DataGrid>
71 <asp:Label ID="Label1" runat="server"></asp:Label>
72 </form>
73</body>
74</html>
<%@ Import Namespace="System.Data" %>
2
<%@ Import Namespace="System.Data.SqlClient" %>3
4
<%@ Page Language="C#" %>5
6
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">7
8
<script runat="server">9
/* 
10
(C) OOMusou 2007 http://oomusou.cnblogs.com11
12
Filename : DataGrid_DataKeyField.aspx13
Compiler : Visual Studio 2005 / C# 2.0 / ASP.NET 2.014
Description : Demo how to get RowIndex in DataGrid's LinkButton15
Release : 06/26/2007 1.016
*/17
protected void Page_Load(object sender, EventArgs e) {18
if (!IsPostBack) 19
DataGrid1_DataBind();20
}21
22
protected void DataGrid1_DataBind() {23
string strSQL = "SELECT TOP 10 " +24
"fname," +25
"lname " +26
"FROM employee";27
SqlConnection con = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=pubs;Integrated Security=True");28
SqlDataAdapter da = new SqlDataAdapter(strSQL, con);29
DataSet ds = new DataSet();30
31
try {32
da.Fill(ds);33
}34
catch (Exception err) {35
Response.Write(err.ToString());36
return;37
}38
finally {39
if ((con != null) && (con.State == ConnectionState.Open))40
con.Close();41
}42
43
DataGrid1.DataSource = ds;44
DataGrid1.DataKeyField = "lname";45
DataGrid1.AutoGenerateColumns = false;46
DataGrid1.DataBind();47
}48
49
protected void DataGrid1_ItemCommand(object source, DataGridCommandEventArgs e) {50
if (e.CommandName == "Select")51
Label1.Text = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();52
}53
</script>54
55
<html xmlns="http://www.w3.org/1999/xhtml">56
<head runat="server">57
<title>Untitled Page</title>58
</head>59
<body>60
<form id="form1" runat="server">61
<asp:DataGrid ID="DataGrid1" runat="server" OnItemCommand="DataGrid1_ItemCommand">62
<Columns>63
<asp:TemplateColumn HeaderText="First Name">64
<ItemTemplate>65
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="Select" Text='<%#DataBinder.Eval(Container.DataItem,"fname")%>'>66
</asp:LinkButton>67
</ItemTemplate>68
</asp:TemplateColumn>69
</Columns>70
</asp:DataGrid>71
<asp:Label ID="Label1" runat="server"></asp:Label>72
</form>73
</body>74
</html>
51行
1protected void DataGrid1_ItemCommand(object source, DataGridCommandEventArgs e) {
2 if (e.CommandName == "Select")
3 Label1.Text = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
4}
5
protected void DataGrid1_ItemCommand(object source, DataGridCommandEventArgs e) {2
if (e.CommandName == "Select")3
Label1.Text = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();4
}5
只需在ItemCommand event的e.Item.ItemIndex就可以輕鬆的抓到RowIndex。
.NET 2.0 GridView
.NET 2.0就改用SqlDataSource和GridView了，LinkButtom一樣得放在TemplateField，但GridView沒有ItemCommand event，取而代之的是RowCommand event。
1<%@ Page Language="C#" %>
2
3<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4
5<script runat="server">
6 /*
7(C) OOMusou 2007 http://oomusou.cnblogs.com
8
9Filename : GridView_RowCommand_RowIndex.aspx
10Compiler : Visual Studio 2005 / C# 2.0 / ASP.NET 2.0
11Description : Demo how to get RowIndex in GridView's LinkButton
12Release : 06/26/2007 1.0
13*/
14 protected void Page_Load(object sender, EventArgs e) {
15 if (!IsPostBack)
16 GridView1_DataBind();
17 }
18
19 protected void GridView1_DataBind() {
20 SqlDataSource1.ConnectionString = @"Data Source=.\sqlexpress;Initial Catalog=pubs;Integrated Security=True";
21 SqlDataSource1.SelectCommand = "SELECT TOP 10 " +
22 "fname," +
23 "lname " +
24 "FROM employee";
25 GridView1.DataSourceID = SqlDataSource1.ID;
26 GridView1.DataKeyNames = new string[] { "lname" };
27 GridView1.AutoGenerateColumns = false;
28 }
29
30 protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e) {
31 if (e.CommandName == "Select") {
32 int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;
33 Label1.Text = GridView1.DataKeys[rowIndex].Value.ToString();
34 }
35 }
36</script>
37
38<html xmlns="http://www.w3.org/1999/xhtml">
39<head runat="server">
40 <title>Untitled Page</title>
41</head>
42<body>
43 <form id="form1" runat="server">
44 <div>
45 <asp:GridView ID="GridView1" runat="server" OnRowCommand="GridView1_RowCommand">
46 <Columns>
47 <asp:TemplateField HeaderText="First Name">
48 <ItemTemplate>
49 <asp:LinkButton ID="LinkButton1" runat="server" CommandName="Select" Text='<%#Eval("fname")%>'></asp:LinkButton>
50 </ItemTemplate>
51 </asp:TemplateField>
52 </Columns>
53 </asp:GridView>
54 </div>
55 <asp:Label ID="Label1" runat="server"></asp:Label>
56 <asp:SqlDataSource ID="SqlDataSource1" runat="server"></asp:SqlDataSource>
57 </form>
58</body>
59</html>
<%@ Page Language="C#" %>2
3
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">4
5
<script runat="server">6
/* 7
(C) OOMusou 2007 http://oomusou.cnblogs.com8
9
Filename : GridView_RowCommand_RowIndex.aspx10
Compiler : Visual Studio 2005 / C# 2.0 / ASP.NET 2.011
Description : Demo how to get RowIndex in GridView's LinkButton12
Release : 06/26/2007 1.013
*/14
protected void Page_Load(object sender, EventArgs e) {15
if (!IsPostBack)16
GridView1_DataBind();17
}18
19
protected void GridView1_DataBind() {20
SqlDataSource1.ConnectionString = @"Data Source=.\sqlexpress;Initial Catalog=pubs;Integrated Security=True";21
SqlDataSource1.SelectCommand = "SELECT TOP 10 " +22
"fname," +23
"lname " +24
"FROM employee";25
GridView1.DataSourceID = SqlDataSource1.ID;26
GridView1.DataKeyNames = new string[] { "lname" };27
GridView1.AutoGenerateColumns = false;28
}29
30
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e) {31
if (e.CommandName == "Select") {32
int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;33
Label1.Text = GridView1.DataKeys[rowIndex].Value.ToString();34
}35
}36
</script>37
38
<html xmlns="http://www.w3.org/1999/xhtml">39
<head runat="server">40
<title>Untitled Page</title>41
</head>42
<body>43
<form id="form1" runat="server">44
<div>45
<asp:GridView ID="GridView1" runat="server" OnRowCommand="GridView1_RowCommand">46
<Columns>47
<asp:TemplateField HeaderText="First Name">48
<ItemTemplate>49
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="Select" Text='<%#Eval("fname")%>'></asp:LinkButton>50
</ItemTemplate>51
</asp:TemplateField>52
</Columns>53
</asp:GridView>54
</div>55
<asp:Label ID="Label1" runat="server"></asp:Label>56
<asp:SqlDataSource ID="SqlDataSource1" runat="server"></asp:SqlDataSource>57
</form>58
</body>59
</html>
最難理解的應該是32行
int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;
e.CommandSource傳的是按下去的LinkButton，不過由於傳回的是Object，就得自行轉成LinkButton，但由於我們想知道的是RowIndex，而LinkButton是包含在GridViewRow內，所以透過NamingContainer傳回目前的GridViewRow，但傳回的是Control，所以需在轉成GridViewRow後才能有RowIndex property。
Conclusion
GridView是DataGrid的繼承人，但不少寫法和DataGrid並不一樣，GridView很多地方比DataGrid更強更好用，但這個例子卻發現GridView比DataGrid麻煩些，或許我沒找到好最好的方法，若有人有更好的方式，歡迎指正，謝謝。
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