public ActionResult EventDetails(int?id)
        {
            var model = new AdminEventDetailsModel();

            if (id.HasValue && Database.Instance.IsValidEventId(id.Value))
            {
                var @event = Database.Instance.GetEventBy(id.Value);

                model.MapFromEntity(@event);
            }

            return(View(model));
        }
        public ActionResult EventDetails(AdminEventDetailsModel model)
        {
            if (ModelState.IsValid)
            {
                var @event = model.Id.HasValue ? Database.Instance.GetEventBy(model.Id.Value) : new Event();

                model.MapToEntity(@event);

                if (model.Id.HasValue)
                {
                    Database.Instance.Update(@event);
                }
                else
                {
                    Database.Instance.SaveNew(@event);
                }

                return(RedirectToAction(nameof(EventOverview)));
            }

            return(View(model));
        }