'Beispiel Task1:
Dim tasks As New List(Of Task)()
   tasks.Add(Task.Factory.StartNew(Sub()
   For Each Dateiname In My.Computer.FileSystem.GetFiles("c:temp")
      'do something
   Next
End Sub))
'Task2 ...
'Task3 ...

 
   For Each Dateiname In My.Computer.FileSystem.GetFiles("c:\temp")
      'Label1.Text = Dateiname
      'do something
      'Progressbar1.value = Progressbar1.value +1 
   Next

 
Delegate Sub WriteTextDelegate(ByVal Target As Label, ByVal Text As String)
 
...
   For Each Dateiname In My.Computer.FileSystem.GetFiles("c:\temp")
      'Label1.Text = Dateiname
      Dim Params(1) As Object
      Params(0) = Label1
      Params(1) = Dateiname
      Me.Invoke(New WriteTextDelegate(AddressOf WriteText), Params)
 
      'do something
      'Progressbar1.value = Progressbar1.value +1 
   Next
...
 
Public Sub WriteText(ByVal Target As Label, ByVal Text As String)
    Target.Text = Text
    Target.Refresh()
End Sub

Joachim