IList<User> users;
using (AppDbContext db = new AppDbContext())
{
    users = db.Users.Where(x => x.Active == true).ToList();
}

// do code to update UI

public interface IUserService : IDisposable
{
    IList<applicationuser> GetUsers();
    IList<AllApplicationUser> GetActiveUsers();
    AllApplicationUser GetUserView(long id);
    applicationuser GetUser(long id);
    void CreateUser(applicationuser user);
    void UpdateUser(applicationuser user);
    void DeleteUser(long id);
    void Save();
    applicationuser Authenticate(string username, string password);
}

class UserService : IUserService
    {
        private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
        private readonly OMEGAEntities _db;
        private bool _disposed = false;

        public UserService()
        {
            _db = new OMEGAEntities();
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!_disposed)
            {
                if (disposing)
                {
                    _db.Dispose();
                }
            }
            _disposed = true;
        }

        public IList<applicationuser> GetUsers()
        {
            // fetch only active users that do not have the role SuperAdmin
            return _db.applicationusers.Where(u => u.roleid != 1 && u.activeflag == true).ToList();
        }

        public IList<AllApplicationUser> GetActiveUsers()
        {
            return _db.AllApplicationUsers.Where(u => u.activeflag == true && u.roleid != 1).ToList();
        }

        public AllApplicationUser GetUserView(long id)
        {
            return _db.AllApplicationUsers.Single(x => x.id == id);
        }

        public applicationuser GetUser(long id)
        {
            return _db.applicationusers.Find(id);
        }

        public void CreateUser(applicationuser user)
        {
            _db.applicationusers.Add(user);
        }

        public void UpdateUser(applicationuser user)
        {
            _db.Entry(user).State = EntityState.Modified;
        }

        public void DeleteUser(long id)
        {
            var user = _db.applicationusers.Find(id);
            _db.applicationusers.Remove(user);
        }

        public void Save()
        {
            _db.SaveChanges();
        }

        public applicationuser Authenticate(string username, string password)
        {
            applicationuser user =
                _db.applicationusers.SingleOrDefault(u => u.loginid.ToLower().Equals(username.ToLower()));

            if (user != null)
            {
                if (Common.Utils.DecryptData(user.password).Equals(password))
                {
                    return user;
                }
            }

            return null;
        }
    }