ListViewDeletedEventArgs.Keys Eigenschaft

Referenz

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.Extensions.dll

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 die Schlüssel für das gelöschte Element 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.IOrderedDictionary

Public ReadOnly Property Keys As IOrderedDictionary

Eigenschaftswert

IOrderedDictionary

Die Schlüssel für das gelöschte Element.

Beispiele

Im folgenden Beispiel wird gezeigt, wie die Keys -Eigenschaft verwendet wird, um auf die Werte der Schlüsselfelder für ein gelöschtes Element 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 ContactsListView_ItemDeleted(Object sender, ListViewDeletedEventArgs 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>ListViewDeletedEventArgs Keys and Values Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewDeletedEventArgs Keys and Values Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
                
      <br/>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"  
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblContacts" width="640px">
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|<< " LastPageText=" >>|"
                NextPageText=" > " PreviousPageText=" < " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Bind("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Bind("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Bind("EmailAddress") %>' />
            </td>
            <td>
              <asp:LinkButton ID="DeleteButton" runat="server" 
                CommandName="Delete" 
                Text="Delete" 
                OnClientClick="return confirm('Are you sure?');" />
            </td>
          </tr>
        </ItemTemplate>
      </asp:ListView>
                 
      <br/><br />
         
      <asp:Label ID="KeysMessageLabel"
        ForeColor="Red"
        runat="server"/>
          
      <br/>
          
      <asp:Label ID="ValuesMessageLabel"
        ForeColor="Red"
        runat="server"/>
            
      <!-- 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="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] FROM Person.Contact"
        DeleteCommand="DELETE FROM Person.Contact WHERE [ContactID] = @ContactID">
          <DeleteParameters>
              <asp:Parameter Name="ContactID" Type="Int32" />
          </DeleteParameters>
      </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 ContactsListView_ItemDeleted(sender As Object, e As ListViewDeletedEventArgs)

    ' Display the value of the key fields in the Keys property.
    KeysMessageLabel.Text = _
      "The key fields for the deleted record are: <br/>"

    For Each entry As DictionaryEntry In e.Keys
      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/>"

    For Each entry As DictionaryEntry In e.Values
      DisplayValue(entry, ValuesMessageLabel)
    Next
  End Sub

  Sub DisplayValue(entry As DictionaryEntry, 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
      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 id="Head1" runat="server">
    <title>ListViewDeletedEventArgs Keys and Values Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewDeletedEventArgs Keys and Values Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
                
      <br/>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"  
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblContacts" width="640px">
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|<< " LastPageText=" >>|"
                NextPageText=" > " PreviousPageText=" < " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Bind("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Bind("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Bind("EmailAddress") %>' />
            </td>
            <td>
              <asp:LinkButton ID="DeleteButton" runat="server" 
                CommandName="Delete" 
                Text="Delete" 
                OnClientClick="return confirm('Are you sure?');" />
            </td>
          </tr>
        </ItemTemplate>
      </asp:ListView>
                 
      <br/><br />
         
      <asp:Label ID="KeysMessageLabel"
        ForeColor="Red"
        runat="server"/>
          
      <br/>
          
      <asp:Label ID="ValuesMessageLabel"
        ForeColor="Red"
        runat="server"/>
            
      <!-- 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="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] FROM Person.Contact"
        DeleteCommand="DELETE FROM Person.Contact WHERE [ContactID] = @ContactID">
          <DeleteParameters>
              <asp:Parameter Name="ContactID" Type="Int32" />
          </DeleteParameters>
      </asp:SqlDataSource>

    </form>
  </body>
</html>

Hinweise

Verwenden Sie die Keys -Eigenschaft, um auf die Werte der Schlüsselfelder (wie von der ListView.DataKeyNames -Eigenschaft angegeben) für ein gelöschtes Element zuzugreifen. Sie können diese Werte beispielsweise verwenden, um ein Protokoll mit gelöschten Elementen zu speichern.

Hinweis

Diese Eigenschaft enthält nur die Schlüsselfelder. Verwenden Sie Values die -Eigenschaft, um auf die Felder ohne Schlüssel zuzugreifen.

Die Keys-Eigenschaft gibt ein Objekt zurück, das die IOrderedDictionary-Schnittstelle implementiert. Das -Objekt enthält DictionaryEntry -Objekte, die die Schlüsselfelder des gelöschten Elements darstellen.

Gilt für:

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