ListViewDeletedEventArgs.Keys Propiedad

Referencia

Definición

Espacio de nombres:: System.Web.UI.WebControls

Ensamblado:: System.Web.Extensions.dll

Importante

Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.

Obtiene la clave o las claves para el elemento eliminado.

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

Valor de propiedad

IOrderedDictionary

Clave o claves para el elemento eliminado.

Ejemplos

En el ejemplo siguiente se muestra cómo usar la Keys propiedad para tener acceso a los valores de los campos clave de un elemento eliminado.

<%@ 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>

Comentarios

Utilice la Keys propiedad para tener acceso a los valores de los campos de clave (según lo especificado por la ListView.DataKeyNames propiedad) para un elemento eliminado. Por ejemplo, puede usar estos valores para mantener un registro de elementos eliminados.

Nota

Esta propiedad contiene solo los campos clave. Para acceder a los campos que no son de clave, use la Values propiedad .

La propiedad Keys devuelve un objeto que implementa la interfaz IOrderedDictionary. El objeto contiene DictionaryEntry objetos que representan los campos clave del elemento eliminado.

Se aplica a

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