CapRaffle.Domain.Implementation.StatisticRepository.UniqueNumberOfRaffleParticipantsInCategory C# (CSharp) Method

        private int UniqueNumberOfRaffleParticipantsInCategory()
        {
            var participants = context.UserEvents.Where(x => x.Event.CategoryId == categoryId).GroupBy(x => x.UserEmail).ToList();
            var winners = context.Winners.Where(x => x.Event.CategoryId == categoryId).GroupBy(x => x.UserEmail).ToList();
            var unique = new HashSet<string>();
            participants.ForEach(x => unique.Add(x.Key));
            winners.ForEach(x => unique.Add(x.Key));
            return unique.Count;
        }