C#

        private string FixOBez()
        {
            SqlConnection dbconn = new SqlConnection(this.sqlconn);

            try
            {
                dbconn.Open();

                SqlDataReader sqlreader = null;
                SqlCommand mycmd = new SqlCommand("SELECT * FROM dbo.testdata", dbconn);
                sqlreader = mycmd.ExecuteReader();

                // Wo kein leerzeichen ist muss eins eingefügt werden
                while (sqlreader.Read())
                {
                    string obez = sqlreader["O_BEZ"].ToString();
                    string okuerzel = sqlreader["O_KURZ"].ToString();

                    // Neue Bezeichnung holen
                    string[] lines = GetNewOBez(obez);


                    // Neue Bezeichnung schreiben
                    SqlCommand sql2 = new SqlCommand("UPDATE dbo.testdata SET WEB_OBEZ1 = '" + lines[0] + "',WEB_OBEZ2 = '" + lines[1] + "',WEB_OBEZ3 = '" + lines[2] + "' WHERE O_KURZ = '" + okuerzel + "'",dbconn);
                    sql2.ExecuteNonQuery();

                    return "OK";
                }

            }
            catch (Exception ex)
            {
                return ex.Message;
            }

            return "OK";
}

private void mainTreeView_AfterSelect(object sender, TreeViewEventArgs e)
{
    if (mainTreeView.SelectedNode == null) return;    // No selection

    TreeNode selectedNode = mainTreeView.SelectedNode;

    switch (selectedNode.Level)
    {
        case 0:    // Root node
            // Toggle the 'Enabled' state of eight items total (combination of ToolStrip and MenuStrip items)
            // ...
            break;
        case 1:    // Child node (only goes Root->Child at the moment; may expand allowed depth later on but not right now)
            if (selectedNode.Parent.Name == "RootNode1")
            {
                // Toggle items based on child of RootNode1
                // ...
            }
            else if (selectedNode.Parent.Name == "RootNode2")
            {
                // Toggle items differently from RootNode1
                // ...
            }
            break;
    }
}
}