BackgroundWorker. Stop thread execution - vb.net

Question

Good afternoon!
Can you tell me how to stop the execution of a thread? The following code doesn't work:
Private Sub Stop_Click(sender As Object, e As EventArgs) Handles Stop.Click
If BackgroundWorker1.IsBusy Then
If BackgroundWorker1.WorkerSupportsCancellation Then
BackgroundWorker1.CancelAsync()
End If
End If
End Sub

Answer 1

That code does exactly what it is supposed to do, i.e. REQUEST a cancellation. It can't just stop working though, because it has no idea what work is being done. YOU are the one writing the code to do the work so YOU are the one who has to write the code to check whether a cancellation has been requested and to actually perform that cancellation. We have no idea what work you're doing so we have no idea where it is convenient to check whether a cancellation has been requested and what, if any, clean-up may be required in that case. Here's a basic example of what a cancellation might look like though:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Raise the DoWork event in a worker thread.
Me.BackgroundWorker1.RunWorkerAsync()
End Sub
'This method is executed in a worker thread.
Private Sub BackgroundWorker1_DoWork(ByVal sender As Object, _
ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim worker As System.ComponentModel.BackgroundWorker = DirectCast(sender, System.ComponentModel.BackgroundWorker)
For i As Integer = 1 To 100
If worker.CancellationPending Then
'The user has cancelled the background operation.
e.Cancel = True
Exit For
End If
'Raise the ProgressChanged event in the UI thread.
worker.ReportProgress(i, i & " iterations complete")
'Perform some time-consuming operation here.
Threading.Thread.Sleep(250)
Next i
End Sub
'This method is executed in the UI thread.
Private Sub BackgroundWorker1_ProgressChanged(ByVal sender As Object, _
ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Me.ProgressBar1.Value = e.ProgressPercentage
Me.Label1.Text = TryCast(e.UserState, String)
End Sub
'This method is executed in the UI thread.
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, _
ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
If e.Cancelled Then
'The background operation was cancelled.
Me.Label1.Text = "Operation cancelled"
Else
'The background operation completed normally.
Me.Label1.Text = "Operation complete"
End If
End Sub
Private Sub Button1_Click(ByVal sender As Object, _
ByVal e As EventArgs) Handles Button1.Click
'Only cancel the background opertion if there is a background operation in progress.
If Me.BackgroundWorker1.IsBusy Then
Me.BackgroundWorker1.CancelAsync()
End If
End Sub