public DataTable Mydatatable(string s3)
        {
            DataTable inv = new DataTable();
            inv.Clear();
            try
            {
                ReConnection();
                if (sqlcn.State == ConnectionState.Open)
                {
                    using (SqlCommand sqlcom3 = new SqlCommand(s3, this.sqlcn))
                    {
                        SqlDataReader sdr = sqlcom3.ExecuteReader();
                        inv.Load(sdr);
                        sqlcom3.Dispose();
                        sdr.Dispose();
                        sdr.Close();
                    }
                }
                else if (olecn.State == ConnectionState.Open)
                {
                    using (OleDbCommand olecom2 = new OleDbCommand(s3, this.olecn))
                    {
                        OleDbDataReader oledr = olecom2.ExecuteReader();
                        inv.Load(oledr);
                        olecom2.Dispose();
                        oledr.Dispose();
                        oledr.Close();
                    }
                }
                errflag = false;
                return inv;
            }
            catch(Exception err)
            {
                errflag = true;
                return inv;
                throw err;
            }
        }
 

DataTable dt1 = new DataTable();
select_st1 = "select ScTime from sRecords where ScTime in (select max(ScTime) from sRecords)";
dt1 = access_con1.Mydatatable(select_st1);
DataTableReader dbreader = new DataTableReader(dt1);
dbreader.Read();
st1 = Convert.ToString(dbreader.GetValue(dbreader.GetOrdinal("ScTime")));