ControlEventHandler Delegát

Definice

Představuje metodu, která zpracuje ControlAdded ControlRemoved události a Control třídy.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)

Parametry

sender
Object

Zdroj událostiThe source of the event.

e
ControlEventArgs

Obsahující ControlEventArgs data události.A ControlEventArgs that contains the event data.

Příklady

Následující příklad kódu vytvoří Binding , přidá ConvertEventHandler delegáta do Parse událostí a a Format přidá Binding do BindingsCollection TextBox ovládacího prvku prostřednictvím DataBindings Vlastnosti.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. DecimalToCurrencyStringDelegát události, přidaný do Format události, formátuje vázanou hodnotu ( Decimal typ) jako měnu pomocí ToString metody.The DecimalToCurrencyString event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. CurrencyStringToDecimalDelegát události, který je přidán k Parse události, převede hodnotu zobrazenou ovládacím prvkem zpět na Decimal typ.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

Poznámky

Při vytváření ControlEventArgs delegáta identifikujete metodu, která událost zpracuje.When you create a ControlEventArgs delegate, you identify the method that will handle the event. Chcete-li přidružit událost k obslužné rutině události, přidejte do události instanci delegáta.To associate the event with your event handler, add an instance of the delegate to the event. Obslužná rutina události je volána při každém výskytu události, dokud neodeberete delegáta.The event handler is called whenever the event occurs, unless you remove the delegate. Další informace o delegátech obslužných rutin událostí naleznete v tématu manipulace a vyvolávání událostí.For more information about event handler delegates, see Handling and Raising Events.

Metody rozšíření

GetMethodInfo(Delegate)

Získává objekt, který představuje metodu reprezentovanou zadaným delegátem.Gets an object that represents the method represented by the specified delegate.

Platí pro

Viz také