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ControlEventHandler Delegate

Represents the method that will handle the ControlAdded and ControlRemoved events of the Control class.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
Public Delegate Sub ControlEventHandler ( _
	sender As Object, _
	e As ControlEventArgs _
)
'Usage
Dim instance As New ControlEventHandler(AddressOf HandlerMethod)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.Windows.Forms.ControlEventArgs

A ControlEventArgs that contains the event data.

When you create a ControlEventArgs 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 DecimalToCurrencyString event delegate, added to the Format event, formats the bound value (a Decimal type) as currency using the ToString method. The CurrencyStringToDecimal event delegate, added to the Parse event, converts the value displayed by the control back to the Decimal type.

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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