public ActionResult Index(string code)
        {
            var fb = new FacebookClient();
            dynamic result = fb.Post("oauth/access_token", new

            {

                client_id = "570964363013096",

                client_secret = "d6edfe3df4e121a296e8e542a8932154",

                redirect_uri = RedirectUri.AbsoluteUri,

                code = code

            });
            var accessToken = result.access_token;

            //Luu access token ma fb tra ve vao session
            Session["AccessToken"] = accessToken;

            FacebookFriendsModel friends = new FacebookFriendsModel();

            var client = new FacebookClient(Session["accessToken"].ToString());
            dynamic fbresult = client.Get("me/friends");
            var data = fbresult["data"].ToString();

            friends.friendsListing = JsonConvert.DeserializeObject<List<FacebookFriend>>(data);

            dbFirstStepDataContext db = new dbFirstStepDataContext();
            var item = db.EntityUsers.ToList();
            IList<EntityUser> banchung = new List<EntityUser>();

            foreach (var ds in friends.friendsListing)
            {
                var ban = item.Where(g => g.IdFacebook == ds.id).ToList();
                foreach (var item2 in ban)
                {
                    var daco = db.EntityTheoDois.Where(t => t.IdUser == Convert.ToInt16(Request.Cookies["ftid"].Value) && t.IdBanBe == item2.Id).ToList();
                    if (daco.Count() == 0)
                    {
                        banchung.Add(item2);
                        EntityTheoDoi dulieu = new EntityTheoDoi();
                        dulieu.IdUser = Convert.ToInt16(Request.Cookies["ftid"].Value);
                        dulieu.IdBanBe = item2.Id;
                        dulieu.TrangThai = 0;
                        dulieu.Loaifb = 1;
                        db.EntityTheoDois.InsertOnSubmit(dulieu);
                        db.SubmitChanges();
                    }
                }
            }
            return RedirectToAction("TimBan", "BanBe");
        }
        // một là thêm bạn mới
        // follow ban be fb
        public string Follow(int IdBanBe)
        {
            try
            {
                int idlogin= Convert.ToInt16(Request.Cookies["ftid"].Value);

                dbFirstStepDataContext db = new dbFirstStepDataContext();

                var user = db.EntityTheoDois.Where(g=>g.IdUser== idlogin&& g.IdBanBe== IdBanBe).FirstOrDefault();
                if (user != null)
                {
                    user.TrangThai = 1;
                    db.SubmitChanges();
                }
                else
                {
                    EntityTheoDoi theodoi = new EntityTheoDoi();
                    theodoi.IdUser = idlogin;
                    theodoi.IdBanBe = IdBanBe;
                    theodoi.TrangThai = 1;
                    theodoi.Loaifb = 1;
                    theodoi.Date = DateTime.Now;
                    db.EntityTheoDois.InsertOnSubmit(theodoi);
                    db.SubmitChanges();
                }
                HoatDongModel.AddHoatDong(idlogin, IdBanBe, 1, 0);
                return "complete";
            }
            catch { return "error"; }
        }