public override bool CheckRepeatedTest() { try { if (DB_Connection != null && DB_Connection.State == ConnectionState.Open) { MySqlCommand command = DB_Connection.CreateCommand(); command.CommandText = "SELECT * FROM " + SqlTable + " WHERE sn=" + SerialNumber + " AND test_flag=1;"; MySqlDataReader reader = command.ExecuteReader(); if (reader.Read() && reader["sn"].ToString().Contains(SerialNumber)) { DB_Connection.Close(); return(true); } DB_Connection.Close(); return(false); } else { return(false); } } catch (Exception e) { Debug.WriteLine("Exception: " + e.Message); return(false); } }