实体框架没有保存上下文的子对象

我试图与实体框架的工作，但我遇到了一个问题，我的设计。我的UserProfile类有三个字段，UserId、UserName和jk_userHandle，前两个字段更新，当我对对象进行更改时可以保存。然而，我甚至不能创建一个非空版本jk_userHandle。我不确定哪里出错了。

我已经google/stackoverflow这个到地狱，并问了我办公室的人，似乎没有人知道-_-

public class UsersContext : DbContext
    {
        public UsersContext()
            : base("DefaultConnection")
        {
        }
public DbSet<UserProfile> UserProfiles { get; set; }
public void changeDataItem_edit(UserProfile choice, jk_userProfile model)
        {
            var found = UserProfiles.Find(choice.UserId); //finds prof
            if (found == null) throw new KeyNotFoundException();
            UserProfile tempProfile = choice;
            tempProfile.jk_userHandle = model;
/*
stuff i found on stackoverflow, but 
found.jk_userHandle = model;
or
found.jk_userHandle.biography = model.biography
don't work either. In all scenarios, when I step through i see my dbset's value change, but will not persist out of the http post. I've tried db.SaveChanges() (outside this function call) as well.
Stackoverflow link: http://stackoverflow.com/questions/7850774/updating-a-reference-to-a-child-object-in-entity-framework-4-1-codefirst
*/
            this.Entry(found).CurrentValues.SetValues(tempProfile);
            found.jk_userHandle = tempProfile.jk_userHandle;
            this.SaveChanges();
        }
}

下面是userprofile类:

[Table("UserProfile")]
    public class UserProfile
    {
        public jk_userProfile jk_userHandle; //is the handle for the rest of the account info...
        [Key]
        [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
        public int UserId { get; set; }
        public string UserName { get; set; }
        public UserProfile()
        {
            jk_userHandle = new jk_userProfile();
        }
    }

以防万一，这里是jk_userHandle

 public class jk_userProfile
    {
        public string userName { get; set; }
        [DataType(DataType.Date)]
        public string lastLogin { get; set; }

        [DataType(DataType.Date)]
        public string creationDate { get; set; }

        [DataType(DataType.MultilineText)]
        [Display(Name = "Just Connekt Biography", Description = "Write about yourself, favorite movies, shows, activities, what you like to do, etc...")]
        public string biography { get; set; }
        public jk_userProfile()
        {
        }
    }