Unable to cancel application - vb.net

Question

I have an application that copies files into different directories. As the application is running if I click the BtnExit_Click button nothing happens. I'm only able to exit out of the app after it has run through all the files to copy.
This is my code
Private Sub BtnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
BackgroundWorker1.CancelAsync()
Me.Close()
End Sub
Background Worker:
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Me.txtImgCount.Text = iCount
Me.txtImgCount.Update()
Me.fileCount.Text = fCount
Me.fileCount.Update()
Me.txtTotal.Update()
Me.Label8.Text = statusText
Me.Label8.Update()
Application.DoEvents()
Try
Me.RichTextBox1.Text &= (fileFilename)
Application.DoEvents()
Catch ei As DivideByZeroException
Debug.WriteLine("Exception caught: {0}", ei)
Finally
End Try
Try
Me.RichTextBox1.Text &= (imgFilename)
Application.DoEvents()
Catch ea As DivideByZeroException
Debug.WriteLine("Exception caught: {0}", ea)
Finally
End Try
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
RunCopyFiles()
End Sub
Private Sub RunCopyFiles()
BackgroundWorker1.WorkerReportsProgress = True
Dim sFileToFind As String
Dim location As String
'Dim File As String
statusText = "Initiating"
status = "Initiating..."
'Directory Files are located in
location = txtFolderPath.Text
'Directory ICN files are located in
imgLocation = txtSearchICN.Text
'Directory files are to copied into
MoveLocation = CopyToPath
createImgFldr = MoveLocation & "\Figures"
createReportFldr = MoveLocation & "\Reports"
createXMLFldr = MoveLocation & "\XML files"
'Create Figures Folder
If Not IO.Directory.Exists(createImgFldr) Then
IO.Directory.CreateDirectory(createImgFldr)
' MsgBox("folder created" & createFolder)
End If
'Create Reports folder
If Not IO.Directory.Exists(createReportFldr) Then
IO.Directory.CreateDirectory(createReportFldr)
'MsgBox("folder created" & createReportFldr)
End If
'Create XML folder
If Not IO.Directory.Exists(createXMLFldr) Then
IO.Directory.CreateDirectory(createXMLFldr)
' MsgBox("folder created" & createFolder)
End If
'Text file with list of file names
Dim filesToCopy = txtFileName.Text
orphanedFiles = MoveLocation & "\Reports\OrphanedFilesItems.txt"
' Create or overwrite the file.
System.IO.File.Create(orphanedFiles).Dispose()
ListofGraphics = MoveLocation & "\Reports\ListOfGraphics.txt"
' Create or overwrite the file.
System.IO.File.Create(ListofGraphics).Dispose()
Dim removDupBuildLog = MoveLocation & "\Reports\RemvoeDup.txt"
Dim ListLog = MoveLocation & "\Reports\ListOfGraphics.txt"
ListofFiles = MoveLocation & "\Reports\ListOfFiles.txt"
' Create or overwrite the file.
System.IO.File.Create(ListofFiles).Dispose()
MissingFiles = MoveLocation & "\Reports\MissingGraphicList.txt"
' Create or overwrite the file.
System.IO.File.Create(MissingFiles).Dispose()
Dim FILE_NAME As String
FILE_NAME = txtFileName.Text
Dim fileNames = System.IO.File.ReadAllLines(FILE_NAME)
status = "Copying SGML\XML Files"
statusText = "Copying SGML\XML Files..."
fCount = 0
For i = 0 To fileNames.Count() - 1
Dim fileName = fileNames(i)
sFileToFind = location & "\" & fileName & "*.*"
Dim paths = IO.Directory.GetFiles(location, fileName, IO.SearchOption.AllDirectories)
If Not paths.Any() Then
System.IO.File.AppendAllText(orphanedFiles, fileName & vbNewLine)
Else
For Each pathAndFileName As String In paths
If System.IO.File.Exists(pathAndFileName) = True Then
Dim sRegLast = pathAndFileName.Substring(pathAndFileName.LastIndexOf("\") + 1)
Dim toFileLoc = System.IO.Path.Combine(createXMLFldr, sRegLast)
Dim moveToFolder = System.IO.Path.Combine(MoveLocation, "XML files", sRegLast)
'if toFileLoc = XML file exists move it into the XML files folder
If System.IO.File.Exists(toFileLoc) = False Then
System.IO.File.Copy(pathAndFileName, moveToFolder)
System.IO.File.AppendAllText(ListofFiles, sRegLast & vbNewLine)
Application.DoEvents()
fileFilename = (fileName) + vbCrLf
fCount = fCount + 1
'fileCount.Text = fCount
End If
End If
Next
End If
BackgroundWorker1.ReportProgress(100 * (i + 1) / fileNames.Count)
Next
CreateGraphicsFunction()
GetImages()
Application.UseWaitCursor = False
Application.DoEvents()
End Sub

Answer 1

If you look at the code example in the documentation for the BackgroundWorker Class you will see that it checks the worker.CancellationPending property every time through the loop.
So you'll need a couple of changes:
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
RunCopyFiles(worker, e)
End Sub
Private Sub RunCopyFiles(worker As BackgroundWorker, e As DoWorkEventArgs)
... other code here
For Each pathAndFileName As String In paths
... other code here
If worker.CancellationPending Then
e.Cancel = True
Exit Sub
End If
Next
Maybe put another check just after the ReportProgress(...) too.
Also, you will need to set backgroundWorker1.WorkerSupportsCancellation = True.
The Application.UseWaitCursor = False should not be in the worker - put it in the code that calls backgroundWorker1.RunWorkerAsync().
As LarsTech wrote in a comment, you should remove all calls to Application.DoEvents(): problems with it are listed in Use of Application.DoEvents().
Finally, make sure that you are using Option Strict On.