Styjun

Program Logic

I'm running a background worker for reading and writing files. For checking if cancel button is clicked, I've created a method called "check_bgWorkerCancelled()" and this is supposed to handle all the events if cacellation is pending.

Problem

When I click the cancel button, the worker keeps running. When I click back the start button, the old process keeps running.

Code: For checking cancellation

' Method: To check is cancellation is pending
 Private Sub check_bgWorkerCancelled()
 ' check if cancellation is pending
 If bgWorker_Scanner.CancellationPending = True Then
 ' background worker cancel asynchronous operating
 If bgWorker_Scanner.IsBusy Then
 Try 'try to
 ' cancel the threads
 bgWorker_Scanner.CancelAsync()
 ' dispose the background worker
 bgWorker_Scanner.Dispose()
 Catch ex As Exception 'if exception
 ' invoke error
 utils.invoke_msg(3, "Worker Error", ex.Message.ToString)
 Me.Close() 'close form
 End Try
 End If
 isScanning = False 'set scanning to false
 Try
 ' invoke to bypass illegal cross threading UI update
 BeginInvoke(CType(Sub()
 progressBar1.Value = 0
 txtStatus.Text = "Cancelled"
 txtCalmDown.Text = ""
 btnToggleScan.Image = Image.FromFile(Application.StartupPath & "/res/malware_scanner/rocket.png")
 End Sub, MethodInvoker))
 Catch ex As Exception : End Try
 Else
 Exit Sub
 End If
 End Sub

Tried Solutions

I've tried the following solutions, but none worked:

Tried to check for cancellation inside DoWork event

Private Sub bgWorker_Scanner_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bgWorker_Scanner.DoWork
 If bgWorker_Scanner.CancellationPending = True Then
 e.CancelAsync()
 bgWorker_Scanner.dispose()
 End If
End Sub

Tried to check for cancellation and collect garbage

Private Sub bgWorker_Scanner_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bgWorker_Scanner.DoWork
 If bgWorker_Scanner.CancellationPending = True Then
 e.CancelAsync()
 bgWorker_Scanner.dispose()
 GC.Collect()
 End If
End Sub

Tried to do the above inside Try-Catch statements

Private Sub bgWorker_Scanner_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bgWorker_Scanner.DoWork
 If bgWorker_Scanner.CancellationPending = True Then
 If bgWorker_Scanner.IsBusy Then
 Try
 e.CancelAsync()
 bgWorker_Scanner.dispose()
 GC.Collect()
 Catch ex As Exception
 MsgBox(ex.Message.ToString)
 End If
 End If
End Sub

Is there any way to end the background worker without having to close the form completely? Any help is appreciated.