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DetailsViewDeletedEventArgs.Keys Eigenschaft

Definition

Ruft ein sortiertes Wörterbuch mit Name-Wert-Paaren der Schlüsselfelder ab, das die Namen und die Werte der Schlüsselfelder der gelöschten Elemente enthält.

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

Eigenschaftswert

IOrderedDictionary

Ein IOrderedDictionary, das ein sortiertes Wörterbuch der Name-Wert-Paare der Schlüsselfelder enthält, mit dem die zu löschenden Elemente zugeordnet werden.

Beispiele

Im folgenden Codebeispiel 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 StoresDetailView_ItemDeleted(Object sender, 
  DetailsViewDeletedEventArgs 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>DetailsViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewDeletedEventArgs Keys and Values Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogeneratedeletebutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          onitemdeleted="StoresDetailView_ItemDeleted" 
          runat="server">
               
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <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="DetailsViewSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          deletecommand="Delete [Customers] 
            Where [CustomerID]=@CustomerID"
          connectionstring=
            "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </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 StoresDetailView_ItemDeleted(ByVal sender As Object, _
    ByVal e As DetailsViewDeletedEventArgs)

    Dim entry As DictionaryEntry
    Dim i As Integer
    
    ' 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>DetailsViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewDeletedEventArgs Keys and Values Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogeneratedeletebutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          onitemdeleted="StoresDetailView_ItemDeleted" 
          runat="server">
               
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <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="DetailsViewSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          deletecommand="Delete [Customers] 
            Where [CustomerID]=@CustomerID"
          connectionstring=
            "<%$ ConnectionStrings:NorthWindConnectionString%>" 
         runat="server"/>
            
      </form>
  </body>
</html>

Hinweise

Verwenden Sie die Keys Eigenschaft, um auf die Werte der Schlüsselfelder für den Datensatz zuzugreifen, um zu löschen. 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 IOrderedDictionary-Schnittstelle implementiert. Das Objekt enthält DictionaryEntry Objekte, die die Schlüsselfelder des Datensatzes darstellen, die gelöscht werden sollen.

Hinweis

Als Verknüpfung können Sie auch den Indexer des IOrderedDictionary Objekts verwenden, um direkt auf die Feldwerte zuzugreifen.

Gilt für

Siehe auch