public ActionResult Edit(int id, UserViewModel userModel)
        {
            try
            {
                var user            = users.GetList().FirstOrDefault(u => u.Id == id);// использую такой костыль т.к. в availableRewards возвращался неполный объект
                var userAwards      = awards.GetList().Select(a => AwardViewModel.GetViewModel(a, user.GetAwards()));
                var checkedAwards   = userModel.AvailableRewards.Where(a => a.Checked);
                var availableAwards = userAwards.Where(a => checkedAwards.Any(aw => aw.Id == a.Id));
                var deletedAwards   = userAwards.Where(a => !checkedAwards.Any(aw => aw.Id == a.Id));

                foreach (var award in availableAwards)
                {
                    award.Checked = true;
                    users.AddAward(id, award.Id);
                }

                foreach (var award in deletedAwards)
                {
                    award.Checked = false;
                    users.RemoveAward(id, award.Id);
                }

                userModel.AvailableRewards = availableAwards.ToList();
                users.Edit(userModel.ToUser());
                return(RedirectToAction("Index"));
            }
            catch
            {
                return(View());
            }
        }
        private void btn_RewardUser_Click(object sender, EventArgs e)
        {
            var user = dgv_Users.CurrentRow?.DataBoundItem as User;

            if (user != null)
            {
                var form = new UserRewardForm(awardBL.GetList(), user.GetAwards().Select(a => a.Title));

                if (form.ShowDialog() == DialogResult.OK)
                {
                    var awardsNow      = awardBL.GetList().Where(a => user.GetAwards().Any(ua => ua.Title == a.Title));
                    var selectedAwards = awardBL.GetList().Where(a => form.SelectedAwards.Contains(a.Title));

                    var awardToAdd    = selectedAwards.Where(sa => !awardsNow.Any(a => a.Id == sa.Id));
                    var awardToDelete = awardsNow.Where(a => !selectedAwards.Any(sa => sa.Id == a.Id));

                    foreach (var toAdd in awardToAdd)
                    {
                        userBL.AddAward(user.Id, toAdd.Id);
                    }

                    foreach (var toDelete in awardToDelete)
                    {
                        userBL.RemoveAward(user.Id, toDelete.Id);
                    }

                    DisplayUsers();
                }
            }
        }