ConvertEventHandler Delegate
Assembly: System.Windows.Forms (in system.windows.forms.dll)
'Declaration Public Delegate Sub ConvertEventHandler ( _ sender As Object, _ e As ConvertEventArgs _ ) 'Usage Dim instance As New ConvertEventHandler(AddressOf HandlerMethod)
/** @delegate */ public delegate void ConvertEventHandler ( Object sender, ConvertEventArgs e )
JScript supports the use of delegates, but not the declaration of new ones.
Parameters
- sender
The source of the event.
- e
A ConvertEventArgs that contains the event data.
When you create a ConvertEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.
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. The DecimalToCurrency event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. The CurrencyToDecimal event delegate, added to the Parse event, converts the value displayed by the control back to the Decimal type.
Private Sub DecimalToCurrency(sender As Object, cevent As ConvertEventArgs) ' The method converts only to string type. Test this using the DesiredType. If Not cevent.DesiredType Is 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 CurrencyToDecimal(sender As Object, cevent As ConvertEventArgs) ' The method converts only to decimal type. If Not cevent.DesiredType Is GetType(Decimal) Then Return End If ' Converts the string back to decimal using the static ToDecimal method. cevent.Value = Convert.ToDecimal(cevent.Value.ToString()) End Sub Private Sub BindControl() ' Creates the binding first. The OrderAmount is typed as Decimal. Dim b As New Binding("Text", ds, "customers.custToOrders.OrderAmount") ' Adds the delegates to the events. AddHandler b.Format, AddressOf DecimalToCurrency AddHandler b.Parse, AddressOf CurrencyToDecimal text1.DataBindings.Add(b) End Sub
private void DecimalToCurrency(Object sender, ConvertEventArgs cevent)
{
// The method converts only to string type.
// Test this using the DesiredType.
if (!(cevent.get_DesiredType().Equals(String.class.ToType()))) {
return ;
}
// Use the ToString method to format the value as currency ("c").
cevent.set_Value(((System.Decimal)cevent.get_Value()).ToString("c"));
} //DecimalToCurrency
private void CurrencyToDecimal(Object sender, ConvertEventArgs cevent)
{
// The method converts only to decimal type.
if (!(cevent.get_DesiredType().Equals(System.Decimal.class.ToType()))) {
return ;
}
// Converts the string back to decimal
// using the static ToDecimal method.
cevent.set_Value(Convert.ToDecimal(cevent.get_Value().ToString()));
} //CurrencyToDecimal
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 events.
b.add_Format(new ConvertEventHandler(DecimalToCurrency));
b.add_Parse(new ConvertEventHandler(CurrencyToDecimal));
text1.get_DataBindings().Add(b);
} //BindControl
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.