Dim t As Thread
    Dim brun As Boolean
 
    ' Thread starten/stoppen
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        brun = Not brun
 
        If Not t Is Nothing Then
            t.Join()
            t = Nothing
        End If
 
        If brun Then
            t = New Thread(AddressOf tr)
            t.Start()
        End If
    End Sub
 
    ' Thread routine
    Private nc As Integer
    Private Delegate Sub addNodeFromThreadDelegate(ByVal name As String)
 
    Private Sub tr()
        While brun
            nc += 1
 
            Dim name As String = "tn" + nc.ToString()
 
            Me.Invoke(New addNodeFromThreadDelegate(AddressOf _
              addNodeFromThread), New Object() {name})
            Thread.Sleep(2000)
        End While
    End Sub
 
    ' Routine um neue Node einzufügen (läuft im Hauptthread)
    Private Sub addNodeFromThread(ByVal name As String)
        tv.Nodes.Add(name)
    End Sub