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BackgroundWorker.OnProgressChanged Method

Raises the ProgressChanged event.

Namespace: System.ComponentModel
Assembly: System (in system.dll)

protected virtual void OnProgressChanged (
	ProgressChangedEventArgs e
)
protected void OnProgressChanged (
	ProgressChangedEventArgs e
)
protected function OnProgressChanged (
	e : ProgressChangedEventArgs
)
Not applicable.

Parameters

e

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 void CalculateCompleted(object operationState)
{
    CalculatePrimeCompletedEventArgs e =
        operationState as CalculatePrimeCompletedEventArgs;

    OnCalculatePrimeCompleted(e);
}

// This method is invoked via the AsyncOperation object,
// so it is guaranteed to be executed on the correct thread.
private void ReportProgress(object state)
{
    ProgressChangedEventArgs e =
        state as ProgressChangedEventArgs;

    OnProgressChanged(e);
}

protected void OnCalculatePrimeCompleted(
    CalculatePrimeCompletedEventArgs e)
{
    if (CalculatePrimeCompleted != null)
    {
        CalculatePrimeCompleted(this, e);
    }
}

protected void OnProgressChanged(ProgressChangedEventArgs e)
{
    if (ProgressChanged != null)
    {
        ProgressChanged(e);
    }
}

// You are guaranteed to be on the correct thread, as
// this method is invoked via the AsyncOperation object.
private void CalculateCompleted(Object operationState)
{
    CalculatePrimeCompletedEventArgs e = 
        (CalculatePrimeCompletedEventArgs)operationState;
    OnCalculatePrimeCompleted(e);
} 

// You are guaranteed to be on the correct thread, as
// this method is invoked via the AsyncOperation object.
private void ReportProgress(Object state)
{
    ProgressChangedEventArgs e = (ProgressChangedEventArgs)state;
    OnProgressChanged(e);
} 

protected void OnCalculatePrimeCompleted(CalculatePrimeCompletedEventArgs e)
{
    if (calculatePrimeCompleted != null) {
        calculatePrimeCompleted.Invoke(this, e);
    }
} 

protected void OnProgressChanged(ProgressChangedEventArgs e)
{
    if (progressChanged != null) {
        progressChanged.Invoke(e);
    }
} 

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0
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