GridViewDeletedEventArgs.Keys Eigenschaft
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Ruft ein sortiertes Wörterbuch mit Name-Wert-Paaren der Schlüsselfelder für den gelöschten Datensatz ab.
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.IOrderedDictionaryPublic ReadOnly Property Keys As IOrderedDictionaryEigenschaftswert
Ein IOrderedDictionary, das ein sortiertes Wörterbuch mit Name-Wert-Paaren der Schlüsselfelder für den gelöschten Datensatz enthält.
Beispiele
Im folgenden Beispiel wird veranschaulicht, wie die Eigenschaft verwendet wird, um auf die Keys Werte der Schlüsselfelder für einen gelöschten Datensatz zuzugreifen.
<%@ 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 CustomersGridView_RowDeleted(Object sender, GridViewDeletedEventArgs e)
{
// Display the value of the key fields in the Keys property.
KeysMessageLabel.Text =
"The key fields for the deleted record are: <br/>";
foreach (DictionaryEntry entry in e.Keys)
{
DisplayValue(entry, KeysMessageLabel);
}
// Display the value of the non-key fields in the Values
// property.
ValuesMessageLabel.Text =
"The non-key fields for the deleted record are: <br/>";
foreach (DictionaryEntry entry in e.Values)
{
DisplayValue(entry, ValuesMessageLabel);
}
}
void DisplayValue(DictionaryEntry entry, Label displayLabel)
{
// Display the field name contained in the DictionaryEntry object.
if (entry.Key != null)
{
displayLabel.Text += "Name=" + entry.Key.ToString() + ", ";
}
else
{
displayLabel.Text += "Name=null, ";
}
// Display the field value contained in the DictionaryEntry object.
if (entry.Value != null)
{
displayLabel.Text += "Value=" + entry.Value.ToString() + "<br/>";
}
else
{
displayLabel.Text += "Value=null<br/>";
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewDeletedEventArgs Keys and Values Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames property as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogeneratedeletebutton="true"
allowpaging="true"
datakeynames="CustomerID"
onrowdeleted="CustomersGridView_RowDeleted"
runat="server">
</asp:gridview>
<br/>
<asp:label id="KeysMessageLabel"
forecolor="Red"
runat="server"/>
<br/><br/>
<asp:label id="ValuesMessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
deletecommand="Delete from Customers where CustomerID = @CustomerID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</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 CustomersGridView_RowDeleted(ByVal sender As Object, ByVal e As GridViewDeletedEventArgs)
Dim entry As DictionaryEntry
' Display the value of the key fields in the Keys property.
KeysMessageLabel.Text = _
"The key fields for the deleted record are: <br/>"
' In VB, you cannot iterate through the DictionaryEntry objects
' in the Keys property directly. Use the CopyTo method to
' copy the objects to an array first.
Dim keysArray(e.Keys.Count - 1) As DictionaryEntry
e.Keys.CopyTo(keysArray, 0)
' Iterate through the array and display its values.
For Each entry In keysArray
DisplayValue(entry, KeysMessageLabel)
Next
' Display the value of the non-key fields in the Values
' property.
ValuesMessageLabel.Text = _
"The non-key fields for the deleted record are: <br/>"
Dim valuesArray(e.Values.Count - 1) As DictionaryEntry
e.Values.CopyTo(valuesArray, 0)
For Each entry In valuesArray
DisplayValue(entry, ValuesMessageLabel)
Next
End Sub
Sub DisplayValue(ByVal entry As DictionaryEntry, ByVal displayLabel As Label)
' Display the field name contained in the DictionaryEntry object.
If entry.Key IsNot Nothing Then
displayLabel.Text &= "Name=" & entry.Key.ToString() & ", "
Else
displayLabel.Text &= "Name=null, "
End If
' Display the field value contained in the DictionaryEntry object.
If entry.Value IsNot Nothing Then
displayLabel.Text &= "Value=" & entry.Value.ToString() & "<br/>"
Else
displayLabel.Text &= "Value=null<br/>"
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewDeletedEventArgs Keys and Values Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames property as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogeneratedeletebutton="true"
allowpaging="true"
datakeynames="CustomerID"
onrowdeleted="CustomersGridView_RowDeleted"
runat="server">
</asp:gridview>
<br/>
<asp:label id="KeysMessageLabel"
forecolor="Red"
runat="server"/>
<br/><br/>
<asp:label id="ValuesMessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
deletecommand="Delete from Customers where CustomerID = @CustomerID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</asp:sqldatasource>
</form>
</body>
</html>
Hinweise
Verwenden Sie die Keys Eigenschaft, um auf die Werte der Schlüsselfelder (wie durch die DataKeyNames Eigenschaft angegeben) für einen gelöschten Datensatz zuzugreifen. Sie können beispielsweise diese Werte verwenden, um ein Protokoll von gelöschten Datensätzen beizubehalten.
Hinweis
Diese Eigenschaft enthält nur die Schlüsselfelder. Verwenden Sie die Eigenschaft, um auf die Values nicht schlüsselfreien Felder zuzugreifen.
Die Keys-Eigenschaft gibt ein Objekt zurück, das die System.Collections.Specialized.IOrderedDictionary-Schnittstelle implementiert. Das Objekt enthält System.Collections.DictionaryEntry Objekte, die die Schlüsselfelder des gelöschten Datensatzes darstellen.