public async Task <IActionResult> Edit(long?id, Agenda agenda)
        {
            if (id != agenda.Id)
            {
                return(NotFound());
            }

            if (id != null)
            {
                try
                {
                    agenda.IdUser = userManager.GetUserAsync(User).Result.Id;
                    await agendaDAL.GravarAgenda(agenda);
                }
                catch (DbUpdateConcurrencyException)
                {
                    throw;
                }

                return(RedirectToAction("Index"));
            }
            return(View(agenda));
        }