use a method and a certain property value to initialize another instance property in a class initialization.

temp code snippet

public class ReflectionController : ODataController
    {
        private static Logger _logger = LogManager.GetCurrentClassLogger();

        [Queryable]
        public IQueryable<CmsReflection> GetReflections()
        {
            var accessToken = Request.Headers.First(header => header.Key == "AccessToken").Value.First().ToString();
            var db = Utility.GetDbContext(accessToken);

            var reflections = db.Reflections.ToList();
            var reflectionParticipants = db.ReflectionParticipants.ToList();
            var competencies = db.CompetencyLangs.Where(cl => cl.LanguageId == (int)Language.Chinese).ToList();
            var users = from user in db.DIR_Users
                        select new
                        {
                            Id = user.Id,
                            Name = user.Name
                        };

            var cmsReflections = from r in reflections
                                 select new CmsReflection
                                 {
                                     Id = r.Id,
                                     CreatorUserId = r.CreatorUserId,
                                     CreatedTime = r.CreatedTime,
                                     CreatorRole = r.CreatorRole,
                                     Type = r.Type,
                                     CompetencyId = r.CompetencyId,
                                     CompetencyName = (from c in competencies
                                                       where c.Id == r.CompetencyId
                                                       select c).FirstOrDefault().Name,
                                     Subject = r.Subject,
                                     Content = r.Content,
                                     Status = r.Status,
                                     ScoreFromCoach = r.ScoreFromCoach,
                                     ParticipantsId = (from p in reflectionParticipants
                                                       where p.ReflectionId == r.Id
                                                       select p.UserId).ToList(),
                                     CreatorUserName = (from u in users
                                                        where u.Id == r.CreatorUserId
                                                        select u.Name).FirstOrDefault(),
                                     ParticipantsNameString = GetNamesString(ParticipantsId, users)
                                 };

            return new List<CmsReflection>().AsQueryable();
        }
        private string GetNamesString(List<Guid> ids, IEnumerable<dynamic> users)
        {
            var sb = new StringBuilder();

            var filteredUserNames = users.Join(ids, user => user.Id, i => i, (user, i) => { return user.Name; }).ToList();

            foreach (var userName in filteredUserNames)
            {
                sb.AppendLine(userName);
            }

            return sb.ToString();
        }

        public class CmsReflection
        {
            public Guid Id { get; set; }
            public Guid CreatorUserId { get; set; }
            public string CreatorUserName { get; set; }
            public long CreatorRole { get; set; }
            public long Type { get; set; }
            public Guid CompetencyId { get; set; }
            public string CompetencyName { get; set; }
            public string Subject { get; set; }
            public string Content { get; set; }
            public long Status { get; set; }
            public long ScoreFromCoach { get; set; }
            public DateTime CreatedTime { get; set; }

            public List<Guid> ParticipantsId { get; set; }
            public string ParticipantsNameString { get; set; }
        }
    }