vb.net background worker cancel not working - vb.net

Question

I'm having an issue where BackgroundWorker.CancelAsync() isn't working. I have WorkerSupportsCancellation set to TRUE. I am also polling BackgroundWorker1.CancellationPending in DoWork. Here is sample code of what I am trying to achieve. I have background worker looping through a time stamp and assigning a value to Measurement variable. I have a subroutine that queries the last reported Measurement variable and writes to listbox. After 5 loops I send BackgroundWorker.CancelAsync(). I can see the cancellation is pending, but it doesn't actually cancel the background worker. Is this a race condition?
Public Class Form1
Dim Measurement As String
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
BackgroundWorker1.RunWorkerAsync()
Delay(0.5)
For x = 1 To 5
ListBox1.Items.Add(Measurement)
ListBox1.TopIndex = ListBox1.Items.Count - 1
TextBox1.Text = BackgroundWorker1.CancellationPending
Delay(1)
Next
BackgroundWorker1.CancelAsync()
TextBox1.Text = BackgroundWorker1.CancellationPending
ListBox1.Items.Add("Cancel Pend: " & BackgroundWorker1.CancellationPending)
Delay(5)
ListBox1.Items.Add("Busy: " & BackgroundWorker1.IsBusy)
End Sub
Private Sub BackgroundWorker1_DoWork(sender As System.Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
If BackgroundWorker1.CancellationPending = True Then
e.Cancel = True
BackgroundWorker1.Dispose()
Exit Sub
Else
Do
Measurement = Now()
Loop
End If
End Sub
End Class

Answer 1

You just need to move the check for the cancellation inside the Do...Loop otherwise it will be tested only at the start of the DoWork event handler and never after that
Private Sub BackgroundWorker1_DoWork(sender As System.Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
If BackgroundWorker1.CancellationPending = True Then
e.Cancel = True
BackgroundWorker1.Dispose()
Else
Do
If BackgroundWorker1.CancellationPending = True Then
e.Cancel = True
BackgroundWorker1.Dispose()
Exit Do
Else
Measurement = Now()
End If
Loop
End if
End Sub