'Zähler
   Private m_Counter As Int32 = 0
 
   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
     System.EventArgs) Handles Button1.Click
      Dim tn As TreeNode = TreeView1.Nodes(0)
 
      If tn.Text = "Neuer Knoten" Then
 
         'Zähler erhöhen
         m_Counter += 1
 
         tn.Text = "Neuer Knoten " + m_Counter.ToString
 
      End If
 
      'Jeden "unmittelbar!" darunterliegenden Knoten erfassen
      For Each xn As TreeNode In tn.Nodes
         If xn.Text = "Neuer Knoten" Then
 
            'Zähler erhöhen
            m_Counter += 1
 
            xn.Text = "Neuer Knoten " + m_Counter.ToString
 
         End If
 
         'Alle noch tieferen Knoten ebenfalls erfassen
         Call ReadSubNodes(xn)
 
      Next
 
      MsgBox("Es wurden " + m_Counter.ToString + " Knoten umbenannt", _
        MsgBoxStyle.Information, "Hinweis")
 
   End Sub
 
 
   Private Sub ReadSubNodes(ByVal Tn As TreeNode)
      For Each xn As TreeNode In Tn.Nodes
         If xn.Text = "Neuer Knoten" Then
 
            'Zähler erhöhen
            m_Counter += 1
 
            xn.Text = "Neuer Knoten " + m_Counter.ToString
 
         End If
 
         'Alle noch tieferen Knoten ebenfalls erfassen (Rekursiver Aufruf!)
         Call ReadSubNodes(xn)
 
      Next
 
   End Sub

Visual Basic Express 2010, C# Express 2010
Intel? i7 Core 920@2.63 Ghz, 6 GByte DDR3, 1024 MB ATI? Radeon? 5870, Windows 7 Prof. 64 Bit
Gibson SG 61' Reissue ; Ibanez Prestige RG 2550 E, Marshall Valvestate VS100 + Modell Vs412 (4 x 12''), Cubase Studio