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BackgroundWorker.ReportProgress Method (Int32, Object)

Raises the ProgressChanged event.

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

public void ReportProgress(
	int percentProgress,
	Object userState


Type: System.Int32

The percentage, from 0 to 100, of the background operation that is complete.

Type: System.Object

The state object passed to RunWorkerAsync.


The WorkerReportsProgress property is set to false.

If you need the background operation to report on its progress, you can call the ReportProgress method to raise the ProgressChanged event. The WorkerReportsProgress property value must true, or ReportProgress will throw an InvalidOperationException.

It is up to you to implement a meaningful way of measuring your background operation's progress as a percentage of the total task completed.

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

	private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
		// This method will run on a thread other than the UI thread. 
		// Be sure not to manipulate any Windows Forms controls created 
		// on the UI thread from this method.
		backgroundWorker.ReportProgress(0, "Working...");
		Decimal lastlast = 0;
		Decimal last = 1;
		Decimal current;
		if (requestedCount >= 1)
		{ AppendNumber(0); }
		if (requestedCount >= 2)
		{ AppendNumber(1); }
		for (int i = 2; i < requestedCount; ++i)
			// Calculate the number.
			checked { current = lastlast + last; }
			// Introduce some delay to simulate a more complicated calculation.
			backgroundWorker.ReportProgress((100 * i) / requestedCount, "Working...");
			// Get ready for the next iteration.
			lastlast = last;
			last = current;

		backgroundWorker.ReportProgress(100, "Complete!");

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