OleDbConnection conn = new OleDbConnection(Service.connectionString);
                string updateSqlForName = "update manager set username=?, password=? where id=?";
                OleDbCommand cmd = new OleDbCommand(updateSqlForName, conn);
                cmd.Parameters.Add(new OleDbParameter("@username", OleDbType.VarWChar, 50)).Value = tb_newusername.Text.ToString();
                cmd.Parameters.Add(new OleDbParameter("@password", OleDbType.VarWChar, 50)).Value = tb_newpass.Text.ToString();
                cmd.Parameters.Add(new OleDbParameter("@id", OleDbType.VarWChar, 50)).Value = Session["ManagerId"].ToString();

                conn.Open();
                cmd.ExecuteNonQuery();
                Response.Write("<script>alert('修改成功，请您重新登录！')</script>");
                AbandonSession();
                conn.Close();
                conn.Dispose();