Dim tn As TreeNode
        For Each dr As DataRow In MyDataTable.Reminder
            Dim dt As String = CDate(dr("Datum")).Year.ToString()
            If tn Is Nothing OrElse tn.Text <> dt Then
                tn = TreeView1.Nodes.Add(dt)
            End If
            tn.Nodes.Add(dr("Bezeichnung"))
        Next

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov