public bool ContainsCommentSubscriber(IUser theUser) { Check.Argument.IsNotNull(theUser, "theUser"); EntityHelper.EnsureEntityCollection(ref _commentSubscribers, CommentSubscribersInternal); var userName = theUser.UserName; var srcQuery = _commentSubscribers.CreateSourceQuery(); return(CommentSubscribersInternal.Any(u => u.UserName == userName) || (srcQuery != null && srcQuery.Any(u => u.UserName == userName))); }