public bool Validate(string user, string pass)
        {
            bool value = false;
            OdbcConnection con = new OdbcConnection("Driver={MySQL ODBC 5.1 Driver};datasource=localhost;database=conexao;user=root;password=;");

            con.Open();

            string sql = "select * FROM users where user = '" + user + "' AND pass = '" + pass + "';";
            OdbcDataAdapter adp = new OdbcDataAdapter(sql, con);
            DataTable users = new DataTable();
            adp.Fill(users);

            if (users.Rows.Count > 0)
            {
                value =  true;
            }
            else
            {
                value =  false;
            }

            return value;

        }