ProgressBar not updating using a For Each loop - vb.net

Question

I'm copying all the .avi and .png files from one folder into another:
Private Sub CopierSend_Button_Click(sender As Object, e As EventArgs) Handles CopierSend_Button.Click
If MessageBox.Show("Click OK to send media or just Cancel.", "Media Copier", MessageBoxButtons.OKCancel, MessageBoxIcon.Question) = DialogResult.OK Then
For Each foundFile As String In My.Computer.FileSystem.GetFiles(FrapsFolder_, Microsoft.VisualBasic.FileIO.SearchOption.SearchTopLevelOnly, "*.avi", "*.png")
Dim foundFileInfo As New System.IO.FileInfo(foundFile)
My.Computer.FileSystem.CopyFile(foundFile, DestFolder_ & foundFileInfo.Name, Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, Microsoft.VisualBasic.FileIO.UICancelOption.DoNothing)
Next
Else
'Nothing Yet
End If
End Sub
I want to add a ProgressBar which will count every time a file is copied, so I added this code before the For Each loop:
Dim file1() As String = IO.Directory.GetFiles(FrapsFolder_, "*.avi")
Dim file2() As String = IO.Directory.GetFiles(FrapsFolder_, "*.png")
Dim files = file1.Length + file2.Length
Copier_ProgressBar.Step = 1
Copier_ProgressBar.Maximum = files
And added this code inside the For Each loop:
Copier_ProgressBar.Value += 1
Here is all of my code:
Private Sub CopierSend_Button_Click(sender As Object, e As EventArgs) Handles CopierSend_Button.Click
If MessageBox.Show("Click OK to send media or just Cancel.", "Media Copier", MessageBoxButtons.OKCancel, MessageBoxIcon.Question) = DialogResult.OK Then
Dim file1() As String = IO.Directory.GetFiles(FrapsFolder_, "*.avi")
Dim file2() As String = IO.Directory.GetFiles(FrapsFolder_, "*.png")
Dim files = file1.Length + file2.Length
Copier_ProgressBar.Step = 1
Copier_ProgressBar.Maximum = files
For Each foundFile As String In My.Computer.FileSystem.GetFiles(FrapsFolder_, Microsoft.VisualBasic.FileIO.SearchOption.SearchTopLevelOnly, "*.avi", "*.png")
Dim foundFileInfo As New System.IO.FileInfo(foundFile)
My.Computer.FileSystem.CopyFile(foundFile, DestFolder_ & foundFileInfo.Name, Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, Microsoft.VisualBasic.FileIO.UICancelOption.DoNothing)
Copier_ProgressBar.Value += 1
Next
Else
'Nothing Yet
End If
End Sub
The ProgressBar updates, but only after all the files have been copied instead of updating in real time. Any idea?

Answer 1

As it stands it looks like the ProgressBar doesn't do anything until after all the files have copied. That isn't strictly true. Instead your UI is not updating.
Instead you should look into using a BackgroundWoker to report progress. Something like this should do the trick:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'This can also be set using the Designer
BackgroundWorker1.WorkerReportsProgress = True
End Sub
Private Sub CopierSend_Button_Click(sender As Object, e As EventArgs) Handles CopierSend_Button.Click
If MessageBox.Show("Click OK to send media or just Cancel.", "Media Copier", MessageBoxButtons.OKCancel, MessageBoxIcon.Question) = DialogResult.OK Then
Dim file1() As String = IO.Directory.GetFiles(FrapsFolder_, "*.avi")
Dim file2() As String = IO.Directory.GetFiles(FrapsFolder_, "*.png")
Dim files As Integer = file1.Length + file2.Length
Copier_ProgressBar.Step = 1
Copier_ProgressBar.Maximum = files
BackgroundWorker1.RunWorkerAsync()
End If
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
For Each foundFile As String In My.Computer.FileSystem.GetFiles(FrapsFolder_, Microsoft.VisualBasic.FileIO.SearchOption.SearchTopLevelOnly, "*.avi", "*.png")
Dim foundFileInfo As New System.IO.FileInfo(foundFile)
My.Computer.FileSystem.CopyFile(foundFile, DestFolder_ & foundFileInfo.Name, Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, Microsoft.VisualBasic.FileIO.UICancelOption.DoNothing)
BackgroundWorker1.ReportProgress(Copier_ProgressBar.Value + 1)
Next
End Sub
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Copier_ProgressBar.Value = e.ProgressPercentage
End Sub
As an additional note, for best practice, I would consider using Path.Combine instead of concatenating strings together:
My.Computer.FileSystem.CopyFile(foundFile, Path.Combine(DestFolder_, foundFileInfo.Name), Microsoft.VisualBasic.FileIO.UIOption.OnlyErrorDialogs, Microsoft.VisualBasic.FileIO.UICancelOption.DoNothing)