Access Database Problem with Strings when saving data

Hi,

I am trying to save my datas to an Access database but I have a problem. When I try to save my string like 00100000, program is going to save it like 100000. What should I do?

public string KasaNoBul()
        {
            string baglanti = "Provider = Microsoft.ACE.OLEDB.12.0; Data Source = |DataDirectory|\\SarjVeritabani.mdb; Persist Security Info = False;";
            string Kasalar = "SELECT KasaNumarasi FROM KasaKontrol";

            string boskasa = "00000000";

            int i = 0, j = 0;

            string[] Kasa = new string[7] {"10000000", "01000000", "00100000", "00010000", "00001000", "00000100", "00000010"};

            string[] KasaNo = new string[7];

            using (OleDbConnection connection = new OleDbConnection(baglanti))
            {
                using (OleDbCommand command = new OleDbCommand(Kasalar, connection))
                {
                    connection.Open();
                    using (OleDbDataReader reader = command.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            KasaNo[i] = Convert.ToString(reader);
                            i++;
                        }
                    }
                }
            }

            while (j < 7)
            {
                if (KasaNo[j] == null)
                {
                    boskasa = Kasa[j];
                    break;
                }

                j++;
            }

            return boskasa;
        }

Thank you.