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