public bool insertUser(string user, string pass, string hoten, bool gioitinh, DateTime ngay, string diachi, string sdt, string hinh, string email, string quyen)
 {
     try
     {
         user u = new user();
         u.username = user;
         u.password = pass;
         u.hoten = hoten;
         u.gioitinhnam = gioitinh;
         u.ngaysinh = ngay;
         u.diachi = diachi;
         u.sdt = sdt;
         u.hinh = hinh;
         u.email = email;
         u.quyenhang = quyen;
         u.Active = true;
         db.users.InsertOnSubmit(u);
         db.SubmitChanges();
         return true;
     }
     catch
     {
         return false;
     }
 }
 partial void Updateuser(user instance);
 partial void Deleteuser(user instance);
 partial void Insertuser(user instance);