public string UpSync(DuLieu data) { string usr = data.userName; string pwd = data.password; Task task = new Task(); //task = Newtonsoft.Json.JsonConvert.DeserializeObject<Task>(tsk); task = data.task; if (Login(usr, pwd)) { try { TaskMDBEntities db = new TaskMDBEntities(); string id = task.ID; var query = from x in db.Tasks where x.ID == id select x; if (query.ToList().Count==0) { // Neu khong ton tai Task t0 = new Task(); t0 = task; db.Tasks.Add(t0); db.SaveChanges(); return "OK - Da them"; } else { // Neu ton tai Task c = (from x in db.Tasks where x.ID == id select x).FirstOrDefault(); c.Place = task.Place; c.TaskContent = task.TaskContent; c.TaskName = task.TaskName; c.BeginTime = task.BeginTime; c.EndTime = task.EndTime; c.Type = task.Type; db.SaveChanges(); return "OK - Da sua"; } } catch (Exception ex) { return ex.Message; } } return "Dang nhap that bai. Chi tiet: Username="******", Password=" + pwd; }