[RESOLVED] BackgroundWorker Help

[tassa]

Hey guys .

I have this app to copy files with a progressbar... What I'm trying to do is to set the progressbar1.maximum to the number of files in the folder.

But I'm getting a cross-thread error.

This is the error I'm getting:

Cross-thread operation not valid: Control 'ProgressBar1' accessed from another thread than the thread it was created on.

This is where I'm trying to set the ProgressBar1.Maximum:

Private Sub BackgroundWorker1_DoWork1 _
    (ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
 
        Dim worker As System.ComponentModel.BackgroundWorker = DirectCast(sender, System.ComponentModel.BackgroundWorker)
        ProgressBar1.Maximum = My.Computer.FileSystem.GetFiles("C:\From", FileIO.SearchOption.SearchAllSubDirectories, "*").Count
        Dim i As Integer = 1
        For Each file As String In My.Computer.FileSystem.GetFiles("C:\From", FileIO.SearchOption.SearchAllSubDirectories, "*")
            My.Computer.FileSystem.CopyFile(file, String.Concat("E:\", Microsoft.VisualBasic.Right(file, Microsoft.VisualBasic.Len(file) - 3)), True)
            worker.ReportProgress(i, i & " File(s) Copied")
            i += 1
        Next
    End Sub

I got this code from the F1 help of VS

' Check if this method is running on a different thread
    ' than the thread that created the control.
    If Me.textBox1.InvokeRequired Then
        ' It's on a different thread, so use Invoke.
        Dim d As New SetTextCallback(AddressOf SetText)
        Me.Invoke(d, New Object() {[NewText] + " (Invoke)"})
    Else
        ' It's on the same thread, no need for Invoke.
        Me.textBox1.Text = [NewText] + " (No Invoke)"
    End If

How can I adjust it to my needs? What's d?

Thanks in advance !

[minitech]

Create a delegate type for your needs, I'll call it OneArgD. Put it after the "Class/Module name" statement in your file.

Delegate Sub OneArgD(ByVal arg As Object)

Next, you need to use Me.ProgressBar1.Invoke.
Inside your backgroundWorker event handler, where you want to set the Maximum property:

Dim deleg As New OneArgD(AddressOf SetMaximum)
Me.ProgressBar1.Invoke(deleg,My.Computer.FileSystem.GetFiles("C:\From", FileIO.SearchOption.SearchAllSubDirectories, "*").Count)

And finally, add a Private Sub declaration to your class/module...

Private Sub SetMaximum(ByVal max As Object)
Me.ProgressBar1.Maximum = CInt(max)
End Sub

I know it's really annoying to do that, but it's the only way.

[tassa]

Can you give me an example please? (I'm searching MSDN for an example too, just though yours might be clearer)

[minitech]

Sorry, I'm editing it progressively, just keep clicking Refresh to see updates.

[minitech]

Ok, done. See post #2.

[tassa]

Thanks a lot!