FormViewDeletedEventArgs.Keys Eigenschaft

Definition

Ruft ein sortiertes Wörterbuch mit Name-Wert-Paaren der Schlüsselfelder für den gelöschten Datensatz ab.Gets an ordered dictionary of key field name/value pairs for the deleted record.

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 OrderedDictionary, das Name-Wert-Paare der Schlüsselfelder für den gelöschten Datensatz enthält.An OrderedDictionary that contains key field name/value pairs for the deleted record.

Beispiele

Im folgenden Beispiel wird veranschaulicht, wie die-Eigenschaft verwendet wird Keys , um auf die Werte der Schlüsselfelder für einen gelöschten Datensatz zuzugreifen.The following example demonstrates how to use the Keys property to access the values of the key fields for a deleted record.


<%@ 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 EmployeeFormView_ItemDeleted(Object sender, FormViewDeletedEventArgs e)
  {
    // Display the values 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 values 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>FormViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormViewDeletedEventArgs Keys and Values Example</h3>
                       
      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        onitemdeleted="EmployeeFormView_ItemDeleted"  
        runat="server">
        
        <itemtemplate>
        
          <table>
            <tr>
              <td>
                <asp:image id="EmployeeImage"
                  imageurl='<%# Eval("PhotoPath") %>'
                  alternatetext='<%# Eval("LastName") %>' 
                  runat="server"/>
              </td>
              <td>
                <asp:label id="FirstNameLabel"
                  text='<%#Bind("FirstName")%>'
                  font-bold="true"
                  runat="server"/>
                <asp:label id="LastNameLabel"
                  text='<%#Bind("LastName")%>'
                  font-bold="true"
                  runat="server"/>
                <br/>     
                <asp:label id="TitleLabel"
                  text='<%#Bind("Title")%>'
                  runat="server"/>        
              </td>
            </tr>
            <tr>
              <td colspan="2">
                <asp:button id="DeleteButton"
                  text="Delete Record"
                  commandname="Delete"
                  runat="server" />
              </td>
            </tr>
          </table>
        
        </itemtemplate>         
                  
      </asp:formview>
      
      <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="EmployeeSource"
        selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [PhotoPath] From [Employees]"
        deletecommand="Delete [Employees] Where [EmployeeID]=@EmployeeID"
        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 EmployeeFormView_ItemDeleted(ByVal sender As Object, ByVal e As FormViewDeletedEventArgs) Handles EmployeeFormView.ItemDeleted
  
    Dim entry As DictionaryEntry
    
    ' Display the values of the key fields in the Keys property.
    KeysMessageLabel.Text = _
      "The key fields for the deleted record are: <br/>"

    ' In Visual Basic, 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 values 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>FormViewDeletedEventArgs Keys and Values Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormViewDeletedEventArgs Keys and Values Example</h3>
                       
      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        runat="server">
        
        <itemtemplate>
        
          <table>
            <tr>
              <td>
                <asp:image id="EmployeeImage"
                  imageurl='<%# Eval("PhotoPath") %>'
                  alternatetext='<%# Eval("LastName") %>' 
                  runat="server"/>
              </td>
              <td>
                <asp:label id="FirstNameLabel"
                  text='<%#Bind("FirstName")%>'
                  font-bold="true"
                  runat="server"/>
                <asp:label id="LastNameLabel"
                  text='<%#Bind("LastName")%>'
                  font-bold="true"
                  runat="server"/>
                <br/>     
                <asp:label id="TitleLabel"
                  text='<%#Bind("Title")%>'
                  runat="server"/>        
              </td>
            </tr>
            <tr>
              <td colspan="2">
                <asp:button id="DeleteButton"
                  text="Delete Record"
                  commandname="Delete"
                  runat="server" />
              </td>
            </tr>
          </table>
        
        </itemtemplate>         
                  
      </asp:formview>
      
      <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="EmployeeSource"
        selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [PhotoPath] From [Employees]"
        deletecommand="Delete [Employees] Where [EmployeeID]=@EmployeeID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>

Hinweise

Die- Keys Eigenschaft enthält die Werte der Schlüsselfelder, die in der-Eigenschaft eines-Steuer Elements aufgeführt sind DataKeyNames FormView .The Keys property contains the values of the key fields listed in the DataKeyNames property of a FormView control. Verwenden Sie die- Keys Eigenschaft, um auf die Werte der Schlüsselfelder (wie von der- DataKeyNames Eigenschaft angegeben) für einen gelöschten Datensatz zuzugreifen.Use the Keys property to access the values of the key fields (as specified by the DataKeyNames property) for a deleted record. Beispielsweise können Sie diese Werte verwenden, um ein Protokoll von gelöschten Datensätzen zu speichern.For example, you can use these values to keep a log of deleted records.

Hinweis

Diese Eigenschaft enthält nur die Schlüsselfelder, die in der-Eigenschaft angegeben sind DataKeyNames .This property contains only the key fields specified in the DataKeyNames property. Verwenden Sie die-Eigenschaft, um auf die nicht Schlüsselfelder zuzugreifen Values .To access the non-key fields, use the Values property.

Die- Keys Eigenschaft gibt ein OrderedDictionary Objekt zurück, das die- System.Collections.Specialized.IOrderedDictionary Schnittstelle implementiert.The Keys property returns an OrderedDictionary object that implements the System.Collections.Specialized.IOrderedDictionary interface. Das- OrderedDictionary Objekt enthält- System.Collections.DictionaryEntry Objekte, die die Schlüsselfelder des gelöschten Datensatzes darstellen.The OrderedDictionary object contains System.Collections.DictionaryEntry objects that represent the key fields of the deleted record. Um auf die Feldnamen zuzugreifen, verwenden Sie die- Keys Eigenschaft des- OrderedDictionary Objekts.To access the field names, use the Keys property of the OrderedDictionary object. Auf ähnliche Weise können Sie auf die Feldwerte zugreifen, indem Sie die- Values Eigenschaft verwenden.Similarly, you can access the field values by using the Values property.

Hinweis

Als Verknüpfung können Sie auch den Indexer des- OrderedDictionary Objekts verwenden, um auf die Schlüssel Feldwerte zuzugreifen.As a shortcut, you can also use the indexer of the OrderedDictionary object to access the key field values. Der Vorteil bei der Verwendung des Indexers besteht darin, dass Schlüssel Feldwerte direkt zurückgegeben werden.The advantage in using the indexer is that it returns key field values directly. Datenquellen Steuerelemente, die auf der Feld Reihenfolge basieren (z. b AccessDataSource .), können nur über den Index auf Schlüssel Feldwerte zugreifenData source controls that rely on the field order (such as AccessDataSource) can access key field values only by index.

Gilt für:

Siehe auch