Updation of Controls using BackGroundWorker in VB.NET

A Visual Basic backGroundWorker control is used to execute an operation on a seperate thread. If you want to use BackGroundWorker control you have to import System. ComponentModel in to the project namespace.
 
The inheritance hierarchy for BackGroundWorker control is given below.

• System.Object 
• System.MarshalByRefObject 
• System.ComponentModel.Component 
• System.ComponentModel.BackGroundWorker
   

• Site:-  It will get or set ISite of the component. 
• Container:- Gets the IContainer that contains the component. 
• IsBusy:- Determine a value indicating whether the BackGroundWorker is running an Asyncronous operation. 
• DesignMode:- Get a value that indicates whether the component is currently in design mode.
   

• First you will need to create new windows application. 
• On your form you will add a BackGroundWorker, two buttons named btnStart and btnCancel, a ProgressBar named prgThread and a ListBox named lstValues controls. The form will display like below.
  
  
  
   
    
  
• Now you have to add System. ComponentModel namespace on to the Project. 
• Now add the below code.

   Private WithEvents TestWorker As System.ComponentModel.BackgroundWorker
    Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
        btnStart.Enabled = False
        btnCancel.Enabled = True
        lstValues.Items.Clear()
        prgThread.Value = 0
        TestWorker = New System.ComponentModel.BackgroundWorker
        TestWorker.WorkerReportsProgress = True
        TestWorker.WorkerSupportsCancellation = True
        TestWorker.RunWorkerAsync()
    End Sub
    Private Sub TestWorker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles TestWorker.DoWork
        Dim ListText As String
        For Value As Integer = 0 To 100
            If TestWorker.CancellationPending Then
                Exit For
            End If
            ListText = String.Concat("Item #", Value)
            TestWorker.ReportProgress(Value, ListText)
            Threading.Thread.Sleep(100)
        Next
    End Sub
    Private Sub TestWorker_ProgressChanged(ByVal sender As Object, ByVal e As                    System.ComponentModel.ProgressChangedEventArgs) Handles
        TestWorker.ProgressChanged
        prgThread.Value = e.ProgressPercentage
        lstValues.Items.Add(e.UserState)
    End Sub
    Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click
        TestWorker.CancelAsync()
    End Sub
    Private Sub TestWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs)         Handles
        TestWorker.RunWorkerCompleted
        btnStart.Enabled = True
        btnCancel.Enabled = False
    End Sub

OutPut:-