public static Clientes pesquisarDados(int cod)
        {
            try
            {
                con = new OleDbConnection(provedor);
                con.Open();

                cmd = new OleDbCommand("SELECT * FROM  Clientes WHERE codigo = @p1", con);
                cmd.Parameters.Add("@p1", OleDbType.Integer).Value = cod;

                dr = cmd.ExecuteReader();

                if (dr.Read())
                {
                    Clientes c = new Clientes();

                    c.bairro   = dr[2].ToString();
                    c.rua      = dr[3].ToString();
                    c.numero   = Convert.ToInt32(dr[4]);
                    c.dt_nasc  = dr[5].ToString();
                    c.telefone = dr[6].ToString();
                    c.ativo    = Convert.ToBoolean(dr[7]);

                    con.Close();
                    return c;
                }
                else
                {
                    con.Close();
                    return null;
                }
            }
            catch(Exception)
            {
                return null;
            }
        }