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ListViewDeletedEventArgs.Keys Propriedade

  • Referência

Definição

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.Extensions.dll

Obtém a chave ou as chaves para o item excluído.

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 da propriedade

IOrderedDictionary

A chave ou as chaves do item excluído.

Exemplos

O exemplo a seguir mostra como usar a Keys propriedade para acessar os valores dos campos de chave de um item excluído.

<%@ 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>

Comentários

Use a Keys propriedade para acessar os valores dos campos de chave (conforme especificado pela ListView.DataKeyNames propriedade ) para um item excluído. Por exemplo, você pode usar esses valores para manter um log de itens excluídos.

Observação

Essa propriedade contém apenas os campos de chave. Para acessar os campos não chave, use a Values propriedade .

A propriedade de Keys retorna um objeto que implementa a interface de IOrderedDictionary. O objeto contém DictionaryEntry objetos que representam os campos de chave do item excluído.

Aplica-se a

Confira também