Поместить результаты запроса в ComboBox - C#

    private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            {
                DataTable dt = new DataTable();
                string sql = "SELECT distinct T3.TransformDate FROM [dbo].[Reporting_Date] t3  GROUP BY T3.TransformDate";
                dt = ServerCommand.SQLExecute(sql);
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    string newDate =
                        Convert.ToDateTime(dt.Rows[i][0]).ToString("dd.MM.yyyy");
\\\\start and finish ComboBox
                    start.Items.Add(newDate);
                    finish.Items.Add(newDate);
                    start.Text = start.Items[start.Items.Count - 1].ToString();
                    finish.Text = finish.Items[finish.Items.Count - 1].ToString();
                }
            }
            {
\\\Второй запрос
                DataTable dt_new = new DataTable();
                string sql = "select distinct t5.Name from [archiv].[dbo].[skr] t5 ";
                dt_new = ServerCommand.SQLExecute(sql);
                for (int i = 0; i < dt_new.Rows.Count; i++)
                {
 
                   string newText = 
\\\\\не ясно как какой convert вести?
                             Convert.text(dt.Rows[i][0]).ToString();
\\\\\tb ComboBox
                       tb.Items.Add(newText);
                       tb.Text = tb.Items[tb.Items.Count - 1].ToString();
 
                    // }
                }
                // MessageBox.Show("ок");
            }
        }