ControlEventHandler ControlEventHandler ControlEventHandler ControlEventHandler Delegate

定義

表示處理 ControlAdded 類別的 ControlRemovedControl 事件的方法。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)

參數

sender
Object Object Object Object

事件的來源。The source of the event.

e
ControlEventArgs ControlEventArgs ControlEventArgs ControlEventArgs

ControlEventArgs,其中包含事件資料。A ControlEventArgs that contains the event data.

繼承
ControlEventHandlerControlEventHandlerControlEventHandlerControlEventHandler

範例

下列程式碼範例會建立BindingConvertEventHandler將委派加入至BindingsCollection Binding Format Parse和事件TextBox ,並透過,將新增至控制項的。DataBindingsproperty.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. 加入DecimalToCurrencyString Decimal至事件的事件委派會使用ToString方法, 將系結值 (類型) 格式化為貨幣。 FormatThe DecimalToCurrencyString event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. 事件委派 (加入Parse至事件) 會將控制項所顯示的值, 轉換回該Decimal類型。 CurrencyStringToDecimalThe 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 'BindControl


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 'DecimalToCurrencyString


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 'CurrencyStringToDecimal

備註

建立 ControlEventArgs 委派時,必須識別處理事件的方法。When you create a ControlEventArgs delegate, you identify the method that will handle the event. 若要使事件與您的事件處理常式產生關聯,請將委派的執行個體 (Instance) 加入至事件。To associate the event with your event handler, add an instance of the delegate to the event. 除非您移除委派,否則每當事件發生時就會呼叫事件處理常式。The event handler is called whenever the event occurs, unless you remove the delegate. 如需事件處理常式委派的詳細資訊, 請參閱處理和引發事件For more information about event handler delegates, see Handling and Raising Events.

擴充方法

GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。Gets an object that represents the method represented by the specified delegate.

適用於

另請參閱