ListViewUpdateEventArgs.Keys Properti
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Mendapatkan kamus pasangan nama/nilai bidang yang mewakili kunci atau kunci item yang akan diperbarui.
public:
property System::Collections::Specialized::IOrderedDictionary ^ Keys { System::Collections::Specialized::IOrderedDictionary ^ get(); };
public System.Collections.Specialized.IOrderedDictionary Keys { get; }
member this.Keys : System.Collections.Specialized.IOrderedDictionary
Public ReadOnly Property Keys As IOrderedDictionary
Nilai Properti
Pasangan nama bidang/nilai yang mewakili kunci atau kunci item yang akan diperbarui.
Contoh
Contoh berikut menunjukkan cara menggunakan Keys properti untuk mengakses nilai bidang kunci untuk rekaman yang sedang diperbarui.
Penting
Contoh ini memiliki kotak teks yang menerima input pengguna, yang merupakan potensi ancaman keamanan. Secara default, ASP.NET halaman Web memvalidasi bahwa input pengguna tidak menyertakan elemen skrip atau HTML. Untuk informasi selengkapnya, lihat Gambaran Umum Eksploitasi Skrip.
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void Page_Load()
{
Message.Text = String.Empty;
}
//<Snippet2>
void UnitMeasureListView_ItemUpdating(Object sender, ListViewUpdateEventArgs e)
{
// Use the Keys property to retrieve the key field value
String keyValue = e.Keys[0].ToString().Trim();
// Cancel the update operation if the user attempts to
// edit a protected record. In this example, unit measure
// codes with 3 letters are protected.
if (keyValue.Length == 3)
{
Message.Text = "You cannot update this record. " +
" Unit Measure Code " + keyValue + " is protected.";
e.Cancel = true;
}
}
//</Snippet2>
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListViewUpdateEventArgs Keys Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ListViewUpdateEventArgs Keys Example</h3>
<asp:Label ID="Message"
ForeColor="Red"
runat="server"/>
<br/>
<asp:ListView ID="UnitMeasureListView"
DataSourceID="UnitMeasureDataSource"
DataKeyNames="UnitMeasureCode"
OnItemUpdating="UnitMeasureListView_ItemUpdating"
runat="server">
<LayoutTemplate>
<table width="400px" border="1" id="tblUnit">
<tr runat="server">
<th runat="server"> </th>
<th runat="server">Unit Measure Code</th>
<th runat="server">Name</th>
</tr>
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<td>
<asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
</td>
</tr>
</ItemTemplate>
<AlternatingItemTemplate>
<tr style="background-color:#B0C4DE" runat="server">
<td>
<asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
</td>
</tr>
</AlternatingItemTemplate>
<EditItemTemplate>
<tr style="background-color:#4682B4">
<td>
<asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="Update" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:TextBox ID="NameTextBox" runat="server" Text='<%#Bind("Name") %>' MaxLength="50" /><br />
</td>
</tr>
</EditItemTemplate>
</asp:ListView>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="UnitMeasureDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [UnitMeasureCode], [Name] FROM Production.UnitMeasure"
UpdateCommand="UPDATE Production.UnitMeasure
SET [Name] = @Name
WHERE [UnitMeasureCode] = @UnitMeasureCode">
</asp:SqlDataSource>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub Page_Load()
Message.Text = String.Empty
End Sub 'Page_Load
Sub UnitMeasureListView_ItemUpdating(ByVal sender As Object, ByVal e As ListViewUpdateEventArgs)
' Use the Keys property to retrieve the key field value
Dim keyValue As String = e.Keys(0).ToString().Trim()
' Cancel the update operation if the user attempts to
' edit a protected record. In this example, unit measure
' codes with 3 letters are protected.
If keyValue.Length = 3 Then
Message.Text = "You cannot update this record. " & _
" Unit Measure Code " & keyValue & " is protected."
e.Cancel = True
End If
End Sub 'UnitMeasureListView_ItemUpdating
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListViewUpdateEventArgs Keys Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>ListViewUpdateEventArgs Keys Example</h3>
<asp:Label ID="Message"
ForeColor="Red"
runat="server"/>
<br/>
<asp:ListView ID="UnitMeasureListView"
DataSourceID="UnitMeasureDataSource"
DataKeyNames="UnitMeasureCode"
OnItemUpdating="UnitMeasureListView_ItemUpdating"
runat="server">
<LayoutTemplate>
<table width="400px" border="1" id="tblUnit">
<tr runat="server">
<th runat="server"> </th>
<th runat="server">Unit Measure Code</th>
<th runat="server">Name</th>
</tr>
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<td>
<asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
</td>
</tr>
</ItemTemplate>
<AlternatingItemTemplate>
<tr style="background-color:#B0C4DE" runat="server">
<td>
<asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
</td>
</tr>
</AlternatingItemTemplate>
<EditItemTemplate>
<tr style="background-color:#4682B4">
<td>
<asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="Update" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" />
</td>
<td>
<asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
</td>
<td>
<asp:TextBox ID="NameTextBox" runat="server" Text='<%#Bind("Name") %>' MaxLength="50" /><br />
</td>
</tr>
</EditItemTemplate>
</asp:ListView>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="UnitMeasureDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [UnitMeasureCode], [Name] FROM Production.UnitMeasure"
UpdateCommand="UPDATE Production.UnitMeasure
SET [Name] = @Name
WHERE [UnitMeasureCode] = @UnitMeasureCode">
</asp:SqlDataSource>
</form>
</body>
</html>
Keterangan
DataKeyNames Saat properti ListView kontrol diatur, gunakan Keys properti (kamus) untuk mengakses nilai kunci primer dalam item yang akan diperbarui.
Catatan
Untuk mengakses nilai bidang non-kunci, gunakan NewValues properti atau OldValues . Properti NewValues berisi nilai yang diperbarui, dan OldValues properti berisi nilai asli.
Keys Kamus secara otomatis diisi dengan pasangan nama/nilai bidang atau bidang yang ditentukan dalam DataKeyNames properti . Jika beberapa bidang membentuk kunci primer, entri terpisah ditambahkan ke Keys kamus untuk setiap bidang kunci.
Untuk menentukan nama bidang kunci, gunakan DictionaryEntry.Key properti DictionaryEntry objek yang terkandung dalam Keys kamus. Untuk menentukan nilai bidang kunci, gunakan DictionaryEntry.Value properti .