BackgroundWorker code won't copy files -- why?

[walt4]

I was exploring how to use the BackgroundWorker with a very simple app to copy files from one folder to another. The code appears below.

When I click the Copy Folders button (ButtonCopyFoldersClick), it should start the copying process. Instead, as soon as I click the button, the labelCopyingMessage displays the text "Copying completed".

A quick check of the destination folder shows that contents of the source folder have not been copied to the destination folder.

If I take the line My.Computer.FileSystem.CopyDirectory("E:\SourceFolder", "D:\DestinationFolder", True) out of the DoWork sub, and place it in the ButtonCopyFolderClick sub, the files do get copied; so the syntax of the copy code is OK.

What am I missing here? There must be something I've overlooked, but what?

Imports System.Configuration
Imports System.Diagnostics
Imports System.Drawing
Imports System.IO
Imports System.IO.Ports
Imports System.Management
Imports System.Runtime.InteropServices

Public Partial Class MainForm
	Public Sub New()
		Me.InitializeComponent()
	End Sub
	
	Sub ButtonCopyFoldersClick(sender As Object, e As EventArgs)
		BackgroundWorkerCopyFolders.RunWorkerAsync()
	End Sub
	
	Sub BackgroundWorkerCopyFoldersDoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs)
		labelCopyingMessage.Text = "Copying folder to destination"
		My.Computer.FileSystem.CopyDirectory("E:\SourceFolder", "D:\DestinationFolder", True)
	End Sub
	
	Sub BackgroundWorkerCopyFoldersRunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs)
		labelCopyingMessage.Text = "Copying completed"
	End Sub
	
End Class

[dolot]

Where is BackgroundWorkerCopyFolders being defined? I don't see anything that connects the sub BackgroundWorkerCopyFoldersDoWork to the BackgroundWorkerCopyFolders object. For that matter, I can't tell how BackgroundWorkerCopyFoldersRunWorkerCompleted is being hooked up either. Maybe it's my ignorance of the matter.

[techgnome]

Nope, dolt, you're not missing anything, the OP is... I don't see any Handles clause on any of the subs... so there's no events being handled. So I don't even see how ButtonCopyFoldersClick is event fired off... so that's problem 1. Problem 2 is that the DoWork and Completed subs are not hooked up as event handlers either. so even if ButtonCopyFoldersClick did run, the events in the BGW wouldn't fire off.

-tg

[walt4]

Techgnome, the lack of handles was the issue. The code I posted was created in SharpDevelop, and apparently it manages the handles differently.

I created the following code using VB2008, which works:

Imports System.Configuration
Imports System.Diagnostics
Imports System.Drawing
Imports System.IO
Imports System.IO.Ports
Imports System.Management
Imports System.Runtime.InteropServices
Imports System.ComponentModel

Public Class Form1

    Private Sub ButtonCopyFoldersClick_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonCopyFoldersClick.Click
        labelCopyingMessage.Text = "Copying folder to destination"
        BackgroundWorkerCopyFolders.RunWorkerAsync()
    End Sub

    Private Sub BackgroundWorkerCopyFolders_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorkerCopyFolders.DoWork
        My.Computer.FileSystem.CopyDirectory("E:\SourceFolder", "D:\DestinationFolder", True)
    End Sub

    Private Sub BackgroundWorkerCopyFolders_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorkerCopyFolders.RunWorkerCompleted
        labelCopyingMessage.Text = "Copying completed"
    End Sub
End Class

The original SharpDevelop sub headers are formatted as follows:

Sub BackgroundWorkerCopyFoldersDoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs)

and

Sub BackgroundWorkerCopyFoldersRunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs)

When I edit these to the following...

Private Sub BackgroundWorkerCopyFoldersDoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorkerCopyFolders.DoWork

and

Private Sub BackgroundWorkerCopyFoldersRunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorkerCopyFolders.RunWorkerCompleted

...I get an error: The handles clause requires a WithEvents variable.

As someone with limited programming experience, I'm not sure how to correct this. Can anyone offer some guidance on how to get the handles to work in SharpDevelop?

[dolot]

Never worked with SharpDevelop - always used Visual Studio.

[techgnome]

well somewhere there is a Dim BackgroundWorkerCopyFolders as .... it needs to have a WithEvents clause added to it.

-tg

[walt4]

I managed to find the answer to the handles problem on the SharpDevelop Forum (Here), and thought I'd post it here for the benefit of others who might be having a similar problem.

In the Designer version of the form, the line declaring the background worker has to be changed.

Original code:
Public backgroundWorkerCopyFolders As System.ComponentModel.BackgroundWorker
Amended code:
Friend WithEvents backgroundWorkerCopyFolders As System.ComponentModel.BackgroundWorker

This change enables the edited versions of the SharpDevelop headers (below) to work.

Private Sub BackgroundWorkerCopyFoldersDoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorkerCopyFolders.DoWork

Private Sub BackgroundWorkerCopyFoldersRunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorkerCopyFolders.RunWorkerCompleted

Now the code works fine and the folders get copied!

Thanks for the heads up on the headers!

[ident]

walt4 techgnone told you that in post Three.

[ident]

BTW what do you mean designer version of the form? I hope you don't mean in the forms designer!!!

[walt4]

I hope you don't mean in the forms designer!!!

Ident, yes, I did mean the forms designer...

In SharpDevelop if you drag a BackgroundWorker onto a form (while in design view) there seems to be no way to edit the properties to add a 'WithEvents' clause other than manually editing the Forms Designer code, which probably isn't a good idea.

The only way to get around this seems to be to delete the BackgroundWorker that was dragged onto the form while in design view, and then declare the BackgroundWorker directly on the form along with the 'WithEvents' clause:

Dim Friend WithEvents backgroundWorkerCopyFolders As New System.ComponentModel.BackgroundWorker

[kareninstructor]

Hello,

If perhaps you were targeting Framework 4.5 (which I see your not) TAP which for many common operations is easier

Public Class Form1
    Private Async Sub cmdCopyFiles_Click(sender As Object, e As EventArgs) Handles cmdCopyFiles.Click
        For Each File As String In IO.Directory.EnumerateFiles(txtStartDirectory.Text)

            Using SourceStream As IO.FileStream = IO.File.Open(File, IO.FileMode.Open)

                Using DestinationStream As IO.FileStream = IO.File.Create(txtEndDirectory.Text & File.Substring(File.LastIndexOf("\"c)))
                    Await SourceStream.CopyToAsync(DestinationStream)
                    Me.Label1.BeginInvoke(New Action(Sub() Label1.Text = "Copying: " & File))
                    Me.Label2.BeginInvoke(New Action(Sub() Label2.Text = "To: " & IO.Path.Combine(txtEndDirectory.Text, IO.Path.GetFileName(File))))
                    Await Task.Delay(100)
                End Using

            End Using

        Next
    End Sub
End Class

In the code above we copy all files in a folder to another folder and the app stays responsive.

[ident]

Kev is there a reason you choose not to invoke once with methodinvoker? curious thats all.

Public Class Form1
 
    Private Sub Foo()
        Me.BeginInvoke(Sub()
                           Me.Label1.Text = ""
                           Me.Label2.Text = ""
                       End Sub)
    End Sub
 
End Class

[kareninstructor]

Kev is there a reason you choose not to invoke once with methodinvoker? curious thats all.

Public Class Form1
 
    Private Sub Foo()
        Me.BeginInvoke(Sub()
                           Me.Label1.Text = ""
                           Me.Label2.Text = ""
                       End Sub)
    End Sub
 
End Class

In the original example I did it has that and a tad more, somehow I did the dual invoke. This is the original were I use a function that returns the file count for copied files

Public Class Form1
    Private Async Sub cmdCopyFilesAsync_Click(sender As Object, e As EventArgs) Handles cmdCopyFilesAsync.Click
        Dim FileCount As Integer = Await CopyFilesAsync()
        MessageBox.Show("Copied " & FileCount.ToString & " files")
    End Sub
    Async Function CopyFilesAsync() As Task(Of Integer)
        Dim FileCount As Integer = 0

        For Each currentFile As String In IO.Directory.EnumerateFiles(txtStartDirectory.Text)

            Using sourceStream As IO.FileStream = IO.File.Open(currentFile, IO.FileMode.Open)

                Using destinationStream As IO.FileStream = IO.File.Create(txtEndDirectory.Text & currentFile.Substring(currentFile.LastIndexOf("\"c)))
                    Await sourceStream.CopyToAsync(destinationStream)
                    Me.BeginInvoke(
                        Sub()
                            lblFrom.Text = "Copying: " & currentFile
                            lblToo.Text = IO.Path.Combine(txtEndDirectory.Text, IO.Path.GetFileName(currentFile))
                        End Sub)

                    ' Slow things down for demoing
                    Await Task.Delay(100)

                    FileCount += 1
                End Using

            End Using

        Next

        Return FileCount

    End Function
End Class

[walt4]

Kevin, that looks like an interesting approach... yes, I'm having to work with some machines that are only on .net 3.5.

[kareninstructor]

Kevin, that looks like an interesting approach... yes, I'm having to work with some machines that are only on .net 3.5.

This should work, place a BackGroundWorker and Progressbar on the form, see the code below, replace the paths to match your requirements. Hope this helps

Imports System.Threading
Public Class Form1
    Delegate Sub UpDateProcessBarDelegate(ByVal FileName As String, ByVal Counter As Integer)
    Private Waiting As Boolean = False
    Private StartDirectory As String = "C:\Data"
    Private EndDirectory As String = "C:\data\0Target"
    Private FileCount As Integer = 0
    Private Sub BackgroundWorker1_RunWorkerCompleted( _
        ByVal sender As Object, _
        ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _
    Handles BackgroundWorker1.RunWorkerCompleted

        MessageBox.Show("Done")

    End Sub
    Private Sub BackgroundWorker1_DoWork( _
        ByVal sender As Object, _
        ByVal e As System.ComponentModel.DoWorkEventArgs) _
    Handles BackgroundWorker1.DoWork

        Dim Files As List(Of String) = _
            (From t In IO.Directory.GetFiles(StartDirectory) _
             Select IO.Path.GetFileName(t)).ToList

        FileCount = Files.Count

        Dim UpdateListBoxDel As UpDateProcessBarDelegate = _
            New UpDateProcessBarDelegate(AddressOf UpdateProgressBar)

        Dim Counter As Integer = 1

        For Each file In Files
            Thread.Sleep(30)

            IO.File.Copy(IO.Path.Combine(StartDirectory, file), _
                         IO.Path.Combine(EndDirectory, file), True)

            If Not BackgroundWorker1.CancellationPending Then
                Me.Invoke(UpdateListBoxDel, file, Counter)
                Counter += 1
            Else
                Exit For
            End If
        Next
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Me.BackgroundWorker1.RunWorkerAsync()
    End Sub
    Public Sub UpdateProgressBar(ByVal FileName As String, ByVal Counter As Integer)
        Me.ProgressBar1.Value = CInt((Counter / Me.FileCount) * 100)
    End Sub
End Class

[pourkascheff]

Wow, as an impartial contributor to this thread, I guarantee #15 is your/our answer since it isn't marked as resolved.

You may alter the way you get/set paths in a dynamic way if you encounter 'path' does not exist exception like so:

Dim NewFolderName As String = "/BACKUP-" & Format(Now, "yyyy-MM-dd-HH-mm-ss")
If Not System.IO.Directory.Exists(FolderBrowser.SelectedPath & NewFolderName) Then
    System.IO.Directory.CreateDirectory(FolderBrowser.SelectedPath & NewFolderName)
End If
Dim DestinitionDirectory = FolderBrowser.SelectedPath & NewFolderName
BackUpThread.RunWorkerAsync()
'New Source:		My.Application.Info.DirectoryPath
'New Destination:	DestinitionDirectory

I wonder what will happen to ProgressChanged event now on.

Edit:
Not sure what is the purpose of Thread.Sleep(30). I commented it and still works fine.

Sorry for waking the dead, I use a different type of calendar in my country.

[techgnome]

For crying outloud Porka... check the best by dates on threads before replying... nothing like replying to a 10 year-old htread to wake the dead....


-tg

[dolot]

For crying outloud Porka... check the best by dates on threads before replying... nothing like replying to a 10 year-old htread to wake the dead....


-tg

ROFL! totally man! I was like "what? What thread is this? I haven't even visited this site in I don't know when."