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BackgroundWorker.OnProgressChanged Method

Raises the ProgressChanged event.

Namespace:  System.ComponentModel
Assemblies:   System.ComponentModel.EventBasedAsync (in System.ComponentModel.EventBasedAsync.dll)
  System (in System.dll)

'Declaration
Protected Overridable Sub OnProgressChanged ( _
	e As ProgressChangedEventArgs _
)

Parameters

e
Type: System.ComponentModel.ProgressChangedEventArgs

An EventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.

The OnProgressChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors

When overriding OnProgressChanged in a derived class, be sure to call the base class's OnProgressChanged method so that registered delegates receive the event.

The following code example demonstrates the use of the OnProgressChanged method to report the progress of an asynchronous operation. This code example is part of a larger example provided for the AsyncOperationManager class.

' This method is invoked via the AsyncOperation object, 
' so it is guaranteed to be executed on the correct thread. 
Private Sub CalculateCompleted(ByVal operationState As Object)
    Dim e As CalculatePrimeCompletedEventArgs = operationState

    OnCalculatePrimeCompleted(e)

End Sub 


' This method is invoked via the AsyncOperation object, 
' so it is guaranteed to be executed on the correct thread. 
Private Sub ReportProgress(ByVal state As Object)
    Dim e As ProgressChangedEventArgs = state

    OnProgressChanged(e)

End Sub 

Protected Sub OnCalculatePrimeCompleted( _
    ByVal e As CalculatePrimeCompletedEventArgs)

    RaiseEvent CalculatePrimeCompleted(Me, e)

End Sub 


Protected Sub OnProgressChanged( _
    ByVal e As ProgressChangedEventArgs)

    RaiseEvent ProgressChanged(e)

End Sub

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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