Binding.Parse Событие

Определение

Происходит при изменении значения элемента управления с привязкой к данным.Occurs when the value of a data-bound control changes.

public:
 event System::Windows::Forms::ConvertEventHandler ^ Parse;
public event System.Windows.Forms.ConvertEventHandler Parse;
member this.Parse : System.Windows.Forms.ConvertEventHandler 
Public Custom Event Parse As ConvertEventHandler 

Примеры

В следующем примере кода создается Binding, добавляется делегат ConvertEventHandler к событиям Parse и Format, а также добавляется Binding в BindingsCollection элемента управления DataBindings с помощью свойства @no__t.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. Делегат события DecimalToCurrencyString, добавленный к событию Format, форматирует связанное значение (тип Decimal) как денежную единицу с помощью метода ToString.The DecimalToCurrencyString event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. Делегат события CurrencyStringToDecimal, добавленный к событию Parse, преобразует значение, отображаемое элементом управления, обратно в тип Decimal.The CurrencyStringToDecimal event delegate, added to the Parse event, converts the value displayed by the control back to the Decimal type.

private:
   void DecimalToCurrencyString( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      // The method converts only to string type. Test this using the 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 )
   {
      // The method converts back to decimal type only.
      if ( cevent->DesiredType != Decimal::typeid )
      {
         return;
      }
      
      // Converts the string back to decimal using the static Parse method.
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }

   void BindControl()
   {
      // Creates the binding first. The OrderAmount is typed as Decimal.
      Binding^ b = gcnew Binding(
         "Text", ds, "customers.custToOrders.OrderAmount" );
      // Add the delegates to the event.
      b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString );
      b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
      text1->DataBindings->Add( b );
   }
private void DecimalToCurrencyString(object sender, ConvertEventArgs cevent)
{
   // The method converts only to string type. Test this using the 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)
{
   // The method converts back to decimal type only.
   if(cevent.DesiredType != typeof(decimal)) return;

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

private void BindControl()
{
   // Creates the binding first. The OrderAmount is typed as Decimal.
   Binding b = new Binding
      ("Text", ds, "customers.custToOrders.OrderAmount");
   // Add the delegates to the event.
   b.Format += new ConvertEventHandler(DecimalToCurrencyString);
   b.Parse += new ConvertEventHandler(CurrencyStringToDecimal);
   text1.DataBindings.Add(b);
}

Private Sub DecimalToCurrencyString(sender As Object, cevent As ConvertEventArgs)
    ' The method converts only to string type. Test this using the DesiredType.
    If cevent.DesiredType IsNot GetType(String) Then
        Exit Sub
    End If
    
    ' Use the ToString method to format the value as currency ("c").
    cevent.Value = CType(cevent.Value, decimal).ToString("c")
End Sub

Private Sub CurrencyStringToDecimal(sender As Object, cevent As ConvertEventArgs)
    ' The method converts back to decimal type only.
    If cevent.DesiredType IsNot GetType(Decimal) Then
        Exit Sub
    End If

    ' Convert the string back to decimal using the shared Parse method.
   cevent.Value = Decimal.Parse(cevent.Value.ToString, _
  NumberStyles.Currency, nothing)

End Sub

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

Комментарии

События Format и Parse позволяют создавать пользовательские форматы для отображения данных.The Format and Parse events allow you to create custom formats for displaying data. Например, если данные в таблице имеют тип Decimal, можно отобразить данные в локальном формате валюты, задав для свойства Value ConvertEventArgs значение отформатированного значения в событии Format.For example, if the data in a table is of type Decimal, you can display the data in the local currency format by setting the Value property of the ConvertEventArgs to the formatted value in the Format event. Поэтому необходимо отформатировать отображаемое значение в событии Parse.You must consequently unformat the displayed value in the Parse event.

Событие Parse возникает при следующих условиях.The Parse event occurs under the following conditions:

Дополнительные сведения об обработке событий см. в разделе обработка и вызов событий.For more information about handling events, see Handling and Raising Events.

Применяется к

Дополнительно