BindingsCollection-Klasse

Stellt eine Auflistung von Binding-Objekten für ein Steuerelement dar.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

Syntax

'Declaration
Public Class BindingsCollection
    Inherits BaseCollection
'Usage
Dim instance As BindingsCollection

public class BindingsCollection : BaseCollection

public ref class BindingsCollection : public BaseCollection

public class BindingsCollection extends BaseCollection

public class BindingsCollection extends BaseCollection

Hinweise

Einfache Datenbindungen werden erstellt, indem Binding-Objekte einer BindingsCollection hinzugefügt werden. Jedes Objekt, das von der Control-Klasse erbt, kann über die DataBindings-Eigenschaft auf die BindingsCollection zugreifen. Eine Liste von Windows-Steuerelementen, die die Datenbindung unterstützen, finden Sie unter der Binding-Klasse.

Beispiel

Im folgenden Beispiel wird die Text-Eigenschaft eines TextBox-Steuerelements an ein Feld in einer Datenbank gebunden.

Private Sub BindTextBoxControl()
   Dim myDataSet As New DataSet()
   ' Insert code to populate the DataSet with tables, columns, and data.

   ' Creates a new Binding object. 
   Dim myBinding As New Binding("Text", myDataSet, _
   "customers.custToOrders.OrderAmount")
   
   ' Adds event delegates for the Parse and Format events.
   AddHandler myBinding.Parse, AddressOf CurrencyToDecimal
   AddHandler myBinding.Format, AddressOf DecimalToCurrency
     
   ' Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding)
End Sub 
    
Private Sub DecimalToCurrency(sender As Object, _
   cevent As ConvertEventArgs)
   ' This method is the Format event handler. Whenever the
   ' control displays a new value, the value is converted from
   ' its native Decimal type to a string. The ToString method
   ' then formats the value as a Currency, by using the
   ' formatting character "c". 
   cevent.Value = CDec(cevent.Value).ToString("c")
End Sub 
    
Private Sub CurrencyToDecimal(sender As Object, _
cevent As ConvertEventArgs)
   ' This method is the Parse event handler. The Parse event
   ' occurs whenever the displayed value changes. The static
   ' Parse method of the Decimal structure converts the 
   ' string back to its native Decimal type. 
   cevent.Value = Decimal.Parse(cevent.Value.ToString(), _
   NumberStyles.Currency, nothing)
   End Sub 

private void BindTextBoxControl()
{
   DataSet myDataSet = new DataSet();
   /* Insert code to populate the DataSet with tables, 
   columns, and data. */

   // Creates a new Binding object. 
   Binding myBinding = new Binding
   ("Text", myDataSet, "customers.custToOrders.OrderAmount");

   // Adds event delegates for the Parse and Format events.
   myBinding.Parse += new ConvertEventHandler(CurrencyToDecimal);
   myBinding.Format += new ConvertEventHandler(DecimalToCurrency);

   // Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding);
}

private void DecimalToCurrency(object sender, 
   ConvertEventArgs cevent)
{
   /* This method is the Format event handler. Whenever the 
   control displays a new value, the value is converted from 
   its native Decimal type to a string. The ToString method 
   then formats the value as a Currency, by using the 
   formatting character "c". */
   cevent.Value = ((decimal) cevent.Value).ToString("c");
}

private void CurrencyToDecimal(object sender, 
   ConvertEventArgs cevent)
{   
   /* This method is the Parse event handler. The Parse event 
   occurs whenever the displayed value changes. The static 
   Parse method of the Decimal structure converts the 
   string back to its native Decimal type. */
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

private:
   void BindTextBoxControl()
   {
      DataSet^ myDataSet = gcnew DataSet;
      /* Insert code to populate the DataSet with tables, 
      columns, and data. */

      // Creates a new Binding object. 
      Binding^ myBinding = gcnew Binding(
         "Text",myDataSet,"customers.custToOrders.OrderAmount" );
      
      // Adds event delegates for the Parse and Format events.
      myBinding->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyToDecimal );
      myBinding->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrency );
      
      // Adds the new Binding to the BindingsCollection.
      text1->DataBindings->Add( myBinding );
   }

   void DecimalToCurrency( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      /* This method is the Format event handler. Whenever the 
      control displays a new value, the value is converted from 
      its native Decimal type to a string. The ToString method 
      then formats the value as a Currency, by using the 
      formatting character "c". */
      cevent->Value = safe_cast<Decimal ^>(cevent->Value)->ToString(  "c" );
   }

   void CurrencyToDecimal( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      /* This method is the Parse event handler. The Parse event 
      occurs whenever the displayed value changes. The static 
      Parse method of the Decimal structure converts the 
      string back to its native Decimal type. */
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }

private void BindTextBoxControl()
{
    DataSet myDataSet = new DataSet();
    /* Insert code to populate the DataSet with tables, 
       columns, and data. 
     */

    // Creates a new Binding object. 
    Binding myBinding = new Binding("Text", myDataSet,
        "customers.custToOrders.OrderAmount");

    // Adds event delegates for the Parse and Format events.
    myBinding.add_Parse(new ConvertEventHandler(CurrencyToDecimal));
    myBinding.add_Format(new ConvertEventHandler(DecimalToCurrency));

    // Adds the new Binding to the BindingsCollection.
    text1.get_DataBindings().Add(myBinding);
} //BindTextBoxControl

private void DecimalToCurrency(Object sender, ConvertEventArgs cevent)
{
    /* This method is the Format event handler. Whenever the 
       control displays a new value, the value is converted from 
       its native Decimal type to a string. The ToString method 
       then formats the value as a Currency, by using the 
       formatting character "c". 
     */
    cevent.set_Value(((System.Decimal)(cevent.get_Value())).ToString("c"));
} //DecimalToCurrency

private void CurrencyToDecimal(Object sender, ConvertEventArgs cevent)
{
    /* This method is the Parse event handler. The Parse event 
       occurs whenever the displayed value changes. The static 
       Parse method of the Decimal structure converts the 
       string back to its native Decimal type. 
     */
    cevent.set_Value(Decimal.Parse(cevent.get_Value().ToString(),
        NumberStyles.Currency, null));
} //CurrencyToDecimal

Vererbungshierarchie

System.Object
   System.MarshalByRefObject
     System.Windows.Forms.BaseCollection
      System.Windows.Forms.BindingsCollection
         System.Windows.Forms.ControlBindingsCollection

Threadsicherheit

Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

.NET Compact Framework

Unterstützt in: 2.0, 1.0

Siehe auch

Referenz

BindingsCollection-Member
System.Windows.Forms-Namespace
CurrencyManager