public static LinkedList <KhachHang> getAllKhachHang()
        {
            LinkedList <KhachHang> list = new LinkedList <KhachHang>();
            DataTable datas             = KhachHang_DB.getAllDataKhachHang();

            for (int i = 0; i < datas.Rows.Count; i++)
            {
                string   _username     = datas.Rows[i].ItemArray[0].ToString();
                string   _password     = datas.Rows[i].ItemArray[1].ToString();
                string   MaKH          = datas.Rows[i].ItemArray[2].ToString();
                string   HoTen         = datas.Rows[i].ItemArray[3].ToString();
                DateTime NgaySinh      = Convert.ToDateTime(datas.Rows[i].ItemArray[4].ToString());
                string   CMND          = datas.Rows[i].ItemArray[5].ToString();
                string   SDT           = datas.Rows[i].ItemArray[6].ToString();
                string   DiaChi        = datas.Rows[i].ItemArray[7].ToString();
                int      Diem          = Convert.ToInt32(datas.Rows[i].ItemArray[8].ToString());
                int      SoLanDangNhap = Convert.ToInt32(datas.Rows[i].ItemArray[9].ToString());
                double   SoTienDaChi   = Convert.ToDouble(datas.Rows[i].ItemArray[10].ToString());
                int      TongDonDaDat  = Convert.ToInt32(datas.Rows[i].ItemArray[11].ToString());
                string   LoaiKH        = Convert.ToString(datas.Rows[i].ItemArray[12].ToString());
                int      TrangThai     = Convert.ToInt32(datas.Rows[i].ItemArray[13].ToString());
                list.AddLast(new KhachHang(_username, _password, MaKH, HoTen, NgaySinh, CMND, SDT, DiaChi, Diem, SoLanDangNhap, SoTienDaChi, TongDonDaDat, LoaiKH, TrangThai));
            }
            return(list);
        }
 public static DataTable getAllDataTable()
 {
     return(KhachHang_DB.getAllDataKhachHang());
 }