UI -> BLL -> WCF Service -> BLL -> DAL(EF)
or
UI -> BLL -> DAL(EF)

public IList<User> UserGetAll()
    {
        var userList = userManager.GetAll();
        return userList;//Not Worked
    }

public IList<User> UserGetAll()
    {
        var userList = userManager.GetAll();

        var result = new List<User>();
        foreach (var user in userList)
        {
            var newUser = new User
            {
                UserId = user.UserId,
                UserName = user.UserName,
                NameSurname = user.NameSurname,
                Password = user.Password,
            };
            result.Add(newUser);
        }
        return result;//Worked
    }

public override IList<User> GetAll()
    {
        using (var dbcontext = new EntityModelContainer())
        {
            var users = dbcontext.User.ToList();
            return users;
        }
    }

public override IList<User> GetAll()
    {
        using (var updatedContext = new EntityModelContainer())
        {
            var users = updatedContext.User.Include("Role").ToList();
            return users;
        }
    }