Dim i As Integer
        TreeView1.Nodes.Clear()
        TreeView1.BeginUpdate()
 
        For i = 0 To 15
            TreeView1.Nodes.Add("Knoten " & i)
        Next i
        TreeView1.EndUpdate()
 
        TreeView1.BeginUpdate()
        Dim tncoll As TreeNodeCollection = TreeView1.Nodes
 
        Dim tnversuch As New TreeNode("Knoten 10")
 
        If tncoll.Contains(tnversuch) Then
            MessageBox.Show("Knoten schon vorhanden " & tncoll.IndexOf( _
              tnversuch).ToString)
        End If
 
        TreeView1.EndUpdate()