Control.LostFocus Event

Definition

Se produit quand le contrôle perd le focus.Occurs when the control loses focus.

public:
 event EventHandler ^ LostFocus;
[System.ComponentModel.Browsable(false)]
public event EventHandler LostFocus;
member this.LostFocus : EventHandler 
Public Custom Event LostFocus As EventHandler 
Attributes

Examples

L’exemple de code suivant illustre la validation du texte pour TextBox1.The following code example demonstrates validating the text for TextBox1. Il montre également comment gérer l’événement LostFocus en affectant à la propriété FileDialog.InitialDirectory le texte contenu dans TextBox1.It also demonstrates handling the LostFocus event by setting the FileDialog.InitialDirectory property to the text in TextBox1. L’exemple de code utilise la méthode ErrorProvider.GetError pour rechercher une erreur avant d’ouvrir la boîte de dialogue fichier.The code example used the ErrorProvider.GetError method to check for an error before opening the file dialog box. Pour exécuter cet exemple, collez le code suivant dans un formulaire contenant une TextBox nommée TextBox1, une OpenFileDialog nommée OpenFileDialog1, une Button nommée Button1et une ErrorProvider nommée ErrorProvider1.To run this example, paste the following code into a form containing a TextBox named TextBox1, an OpenFileDialog named OpenFileDialog1, a Button named Button1, and an ErrorProvider named ErrorProvider1. Vérifiez que tous les événements sont associés à leurs gestionnaires d’événements.Ensure all events are associated with their event handlers.

private:
   void TextBox1_Validating( Object^ sender,
      System::ComponentModel::CancelEventArgs^ e )
   {
      // If nothing is entered,
      // an ArgumentException is caught; if an invalid directory is entered, 
      // a DirectoryNotFoundException is caught. An appropriate error message 
      // is displayed in either case.
      try
      {
         System::IO::DirectoryInfo^ directory = gcnew System::IO::DirectoryInfo( TextBox1->Text );
         directory->GetFiles();
         ErrorProvider1->SetError( TextBox1, "" );
      }
      catch ( System::ArgumentException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "Please enter a directory" );
      }
      catch ( System::IO::DirectoryNotFoundException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "The directory does not exist."
         "Try again with a different directory." );
      }
   }

   // This method handles the LostFocus event for TextBox1 by setting the 
   // dialog's InitialDirectory property to the text in TextBox1.
   void TextBox1_LostFocus( Object^ sender, System::EventArgs^ e )
   {
      OpenFileDialog1->InitialDirectory = TextBox1->Text;
   }

   // This method demonstrates using the ErrorProvider.GetError method 
   // to check for an error before opening the dialog box.
   void Button1_Click( System::Object^ sender, System::EventArgs^ e )
   {
      //If there is no error, then open the dialog box.
      if ( ErrorProvider1->GetError( TextBox1 )->Equals( "" ) )
      {
         ::DialogResult dialogResult = OpenFileDialog1->ShowDialog();
      }
   }
private void textBox1_Validating(object sender, 
    System.ComponentModel.CancelEventArgs e)
{
    // If nothing is entered,
    // an ArgumentException is caught; if an invalid directory is entered, 
    // a DirectoryNotFoundException is caught. An appropriate error message 
    // is displayed in either case.
    try
    {
        System.IO.DirectoryInfo directory = 
            new System.IO.DirectoryInfo(textBox1.Text);
        directory.GetFiles();
        errorProvider1.SetError(textBox1, "");
    }
    catch(System.ArgumentException ex1)
    {
        errorProvider1.SetError(textBox1, "Please enter a directory");
    }
    catch(System.IO.DirectoryNotFoundException ex2)
    {
        errorProvider1.SetError(textBox1, "The directory does not exist." +
            "Try again with a different directory.");
    }
}

// This method handles the LostFocus event for textBox1 by setting the 
// dialog's InitialDirectory property to the text in textBox1.
private void textBox1_LostFocus(object sender, System.EventArgs e)
{
    openFileDialog1.InitialDirectory = textBox1.Text;
}

// This method demonstrates using the ErrorProvider.GetError method 
// to check for an error before opening the dialog box.
private void button1_Click(System.Object sender, System.EventArgs e)
{
    //If there is no error, then open the dialog box.
    if (errorProvider1.GetError(textBox1)=="")
    {
        DialogResult dialogResult = openFileDialog1.ShowDialog();
    }
}
Private Sub TextBox1_Validating(ByVal sender As Object, _
ByVal e As System.ComponentModel.CancelEventArgs) _
Handles TextBox1.Validating

    ' If nothing is entered,
    ' an ArgumentException is caught; if an invalid directory is entered, 
    ' a DirectoryNotFoundException is caught. An appropriate error message 
    ' is displayed in either case.
    Try
        Dim directory As New System.IO.DirectoryInfo(TextBox1.Text)
        directory.GetFiles()
        ErrorProvider1.SetError(TextBox1, "")

    Catch ex1 As System.ArgumentException
        ErrorProvider1.SetError(TextBox1, "Please enter a directory")

    Catch ex2 As System.IO.DirectoryNotFoundException
        ErrorProvider1.SetError(TextBox1, _
        "The directory does not exist." & _
        "Try again with a different directory.")
    End Try

End Sub

' This method handles the LostFocus event for TextBox1 by setting the 
' dialog's InitialDirectory property to the text in TextBox1.
Private Sub TextBox1_LostFocus(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles TextBox1.LostFocus
    OpenFileDialog1.InitialDirectory = TextBox1.Text
End Sub


' This method demonstrates using the ErrorProvider.GetError method 
' to check for an error before opening the dialog box.
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click

    'If there is no error, then open the dialog box.
    If ErrorProvider1.GetError(TextBox1) = "" Then
        Dim dialogResult As DialogResult = OpenFileDialog1.ShowDialog()
    End If

End Sub

Remarks

Lorsque vous modifiez le focus à l’aide du clavier (tabulation, MAJ + TAB, etc.), en appelant les méthodes Select ou SelectNextControl, ou en définissant la propriété ContainerControl.ActiveControl sur le formulaire actuel, les événements de focus se produisent dans l’ordre suivant :When you change the focus by using the keyboard (TAB, SHIFT+TAB, and so on), by calling the Select or SelectNextControl methods, or by setting the ContainerControl.ActiveControl property to the current form, focus events occur in the following order:

  1. Enter

  2. GotFocus

  3. Leave

  4. Validating

  5. Validated

  6. LostFocus

Lorsque vous modifiez le focus à l’aide de la souris ou en appelant la méthode Focus, les événements de focus se produisent dans l’ordre suivant :When you change the focus by using the mouse or by calling the Focus method, focus events occur in the following order:

  1. Enter

  2. GotFocus

  3. LostFocus

  4. Leave

  5. Validating

  6. Validated

Si la propriété CausesValidation est définie sur false, les événements Validating et Validated sont supprimés.If the CausesValidation property is set to false, the Validating and Validated events are suppressed.

Si la propriété Cancel du CancelEventArgs a la valeur true dans le Validating délégué d’événement, tous les événements qui se produisent habituellement après l’événement Validating sont supprimés.If the Cancel property of the CancelEventArgs is set to true in the Validating event delegate, all events that would usually occur after the Validating event are suppressed.

Note

Les événements GotFocus et LostFocus sont des événements de focus de bas niveau qui sont liés aux messages WM_KILLFOCUS et WM_SETFOCUS Windows.The GotFocus and LostFocus events are low-level focus events that are tied to the WM_KILLFOCUS and WM_SETFOCUS Windows messages. En règle générale, les événements GotFocus et LostFocus sont utilisés uniquement lors de la mise à jour de UICues ou lors de l’écriture de contrôles personnalisés.Typically, the GotFocus and LostFocus events are only used when updating UICues or when writing custom controls. Au lieu de cela, les événements Enter et Leave doivent être utilisés pour tous les contrôles, à l’exception de la classe Form, qui utilise les événements Activated et Deactivate.Instead the Enter and Leave events should be used for all controls except the Form class, which uses the Activated and Deactivate events. Pour plus d’informations sur les événements GotFocus et LostFocus, consultez les rubriques WM_KILLFOCUS et WM_KILLFOCUS .For more information about the GotFocus and LostFocus events, see the WM_KILLFOCUS and WM_KILLFOCUS topics.

Caution

N’essayez pas de définir le focus à partir des gestionnaires d’événements Enter, GotFocus, Leave, LostFocus, Validatingou Validated.Do not attempt to set focus from within the Enter, GotFocus, Leave, LostFocus, Validating, or Validated event handlers. Cela peut entraîner l’arrêt de la réponse de votre application ou du système d’exploitation.Doing so can cause your application or the operating system to stop responding. Pour plus d’informations, consultez la rubrique WM_KILLFOCUS .For more information, see the WM_KILLFOCUS topic.

Pour plus d'informations sur la gestion des événements, voir gestion et déclenchement d’événements.For more information about handling events, see Handling and Raising Events.

Applies to

See also