ControlEventHandler Délégué

Définition

Représente la méthode qui gérera les événements ControlAdded et ControlRemoved de la classe Control.Represents the method that will handle the ControlAdded and ControlRemoved events of the Control class.

public delegate void ControlEventHandler(System::Object ^ sender, ControlEventArgs ^ e);
public delegate void ControlEventHandler(object sender, ControlEventArgs e);
type ControlEventHandler = delegate of obj * ControlEventArgs -> unit
Public Delegate Sub ControlEventHandler(sender As Object, e As ControlEventArgs)

Paramètres

sender
Object

Source de l'événement.The source of the event.

e
ControlEventArgs

ControlEventArgs qui contient les données d'événement.A ControlEventArgs that contains the event data.

Héritage
ControlEventHandler

Exemples

L’exemple de code suivant crée Bindingun, ajoute ConvertEventHandler un délégué aux Parse événements BindingsCollection et Format , puis ajoute le Binding au d’un TextBox contrôle par le biais de DataBindings l’événement propriété.The following code example creates a Binding, adds a ConvertEventHandler delegate to both the Parse and Format events, and adds the Binding to the BindingsCollection of a TextBox control through the DataBindings property. Le DecimalToCurrencyString délégué d’événement, ajouté à Format l’événement, met en forme la valeur Decimal liée (un type) en ToString tant que devise à l’aide de la méthode.The DecimalToCurrencyString event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. Le CurrencyStringToDecimal délégué d’événement, ajouté à Parse l’événement, convertit la valeur affichée par Decimal le contrôle au type.The CurrencyStringToDecimal event delegate, added to the Parse event, converts the value displayed by the control back to the Decimal type.

private:
   void BindControl()
   {
      // Create the binding first. The OrderAmount is typed as Decimal.
      Binding^ b = gcnew Binding(
         "Text",ds,"customers.custToOrders.OrderAmount" );
      // Add the delegates to the events.
      b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString );
      b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
      text1->DataBindings->Add( b );
   }

   void DecimalToCurrencyString( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      // Check for the appropriate DesiredType.
      if ( cevent->DesiredType != String::typeid )
      {
         return;
      }

      // Use the ToString method to format the value as currency ("c").
      cevent->Value = ( (Decimal^)(cevent->Value) )->ToString( "c" );
   }

   void CurrencyStringToDecimal( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      // Check for the appropriate DesiredType. 
      if ( cevent->DesiredType != Decimal::typeid )
      {
         return;
      }

      // Convert the string back to decimal using the static Parse method.
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }
private void BindControl()
{
   // Create the binding first. The OrderAmount is typed as Decimal.
   Binding b = new Binding
      ("Text", ds, "customers.custToOrders.OrderAmount");
   // Add the delegates to the events.
   b.Format += new ConvertEventHandler(DecimalToCurrencyString);
   b.Parse += new ConvertEventHandler(CurrencyStringToDecimal);
   text1.DataBindings.Add(b);
}

private void DecimalToCurrencyString(object sender, ConvertEventArgs cevent)
{
   // Check for the appropriate DesiredType.
   if(cevent.DesiredType != typeof(string)) return;

   // Use the ToString method to format the value as currency ("c").
   cevent.Value = ((decimal) cevent.Value).ToString("c");
}

private void CurrencyStringToDecimal(object sender, ConvertEventArgs cevent)
{
   // Check for the appropriate DesiredType. 
   if(cevent.DesiredType != typeof(decimal)) return;

   // Convert the string back to decimal using the static Parse method.
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

Private Sub BindControl()
    ' Create the binding first. The OrderAmount is typed as Decimal.
    Dim b As New Binding("Text", ds, "customers.custToOrders.OrderAmount")
    ' Add the delegates to the events.
    AddHandler b.Format, AddressOf DecimalToCurrencyString
    AddHandler b.Parse, AddressOf CurrencyStringToDecimal
    text1.DataBindings.Add(b)
End Sub


Private Sub DecimalToCurrencyString(sender As Object, cevent As ConvertEventArgs)
    ' Check for the appropriate DesiredType.
    If cevent.DesiredType IsNot GetType(String) Then
        Return
    End If 
    ' Use the ToString method to format the value as currency ("c").
    cevent.Value = CDec(cevent.Value).ToString("c")
End Sub


Private Sub CurrencyStringToDecimal(sender As Object, cevent As ConvertEventArgs)
    ' Check for the appropriate DesiredType. 
    If cevent.DesiredType IsNot GetType(Decimal) Then
        Return
    End If 
    ' Convert the string back to decimal using the static Parse method.
  cevent.Value = Decimal.Parse(cevent.Value.ToString, _
  NumberStyles.Currency, nothing)

End Sub

Remarques

Lorsque vous créez un délégué ControlEventArgs, vous identifiez la méthode qui gérera l'événement.When you create a ControlEventArgs delegate, you identify the method that will handle the event. Pour associer l'événement au gestionnaire d'événements, ajoutez une instance du délégué à l'événement.To associate the event with your event handler, add an instance of the delegate to the event. Le gestionnaire d'événements est appelé chaque fois qu'un événement se produit, sauf si vous supprimez le délégué.The event handler is called whenever the event occurs, unless you remove the delegate. Pour plus d’informations sur les délégués de gestionnaires d’événements, consultez gestion et déclenchement d’événements.For more information about event handler delegates, see Handling and Raising Events.

Méthodes d’extension

GetMethodInfo(Delegate)

Obtient un objet qui représente la méthode représentée par le délégué spécifié.Gets an object that represents the method represented by the specified delegate.

S’applique à

Voir aussi