BackgroundWorker.ReportProgress Method (Int32, Object)

 

Raises the ProgressChanged event.

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

Public Sub ReportProgress (
	percentProgress As Integer,
	userState As Object
)

Parameters

percentProgress
Type: System.Int32

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

userState
Type: System.Object

The state object passed to RunWorkerAsync.

Exception Condition
InvalidOperationException

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 Sub backgroundWorker1_DoWork(sender As Object, e As DoWorkEventArgs)
   ' 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...")
   Dim lastlast As [Decimal] = 0
   Dim last As [Decimal] = 1
   Dim current As [Decimal]
   If requestedCount >= 1 Then
      AppendNumber(0)
   End If
   If requestedCount >= 2 Then
      AppendNumber(1)
   End If
   Dim i As Integer

   While i < requestedCount
      ' Calculate the number.
      current = lastlast + last
      ' Introduce some delay to simulate a more complicated calculation.
      System.Threading.Thread.Sleep(100)
      AppendNumber(current)
      backgroundWorker.ReportProgress(100 * i / requestedCount, "Working...")
      ' Get ready for the next iteration.
      lastlast = last
      last = current
      i += 1
   End While


   backgroundWorker.ReportProgress(100, "Complete!")
 End Sub

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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