ddd, collections of value object - nhibernate

Question

class Feed : Entity {
public Guid Id {get;set;}
public string FeedText {get;set;}
public ISet<FeedUser> FeedUsers {get;set;}
public void AddFeedUser(User user) {
FeedUsers.Add(user.Id);
}
public void RemoveFeedUser(User user) {
FeedUsers.Remove(user.Id);
}
public void MarkUserAsReadFeed(User user)
{
var feedUser = FeedUsers.Find(u=>u.Id == user.Id);
feedUser.Read();
}
}
class FeedUser : ValueObject {
public Guid UserId {get;private set;}
public bool IsRead {get;private set;}
public DateTime? ReadDate=null {get;private set;}
public void Read(){
IsRead = true;
}
public void UnRead(){
IsRead = false;
}
}
In this case FeedUser is Value Object or Entity? I'm confuse because FeedUser no need identity but not 100% immutable (IsRead property changable)
A Feed have a lot of FeedUser. At NHibernate, should I load all FeedUsers property (Lazy Load or Eager loading) for add new FeedUser or remove from list?

Answer 1

Question1: The FeedUser is not a value object since it's mutable and has it's life cycle(but binding with the Feed's lifecycle). In this design, it's a local entity(userId as local identifier).
Question2: I'm afraid you have to load all FeedUsers first.
Indirect answer: If you think it's awkward, you may ask yourself what's the invariant to be protected? what about make FeedUser an aggregate?
class Feed : Entity {
public Guid Id {get;set;}
public string FeedText {get;set;}
public FeedUser AddFeedUser(User user) {
return new FeedUser(id, user); //sorry, I have to confess I'm not a .net guy.
}
}
class FeedUser : Entity {
public Guid id;
public Guid feedId;
public Guid UserId {get;private set;}
public bool IsRead {get;private set;}
public DateTime? ReadDate=null {get;private set;}
public void Read(){
IsRead = true;
}
public void UnRead(){
IsRead = false;
}
}
//FeedUserRepository is responsible for removeing FeedUser