private void LoadPage()
        {
            double reportRevenue = 0;
            int    reportRoom    = 0;
            double reportTime    = 0;

            bills = new BindingList <Bill>(billViewModel.FindAll());
            foreach (var bill in bills)
            {
                bill.CardBookRoom          = cardBookRoomViewModel.FindById(bill.IdCardBookRoom);
                bill.Employee              = employeeViewModel.FindById(bill.IdEmployee);
                bill.CardBookRoom.Room     = roomViewModel.FindById(bill.CardBookRoom.RoomId);
                bill.CardBookRoom.Customer = customerViewModel.FindById(bill.CardBookRoom.CustomerId);
                bill.TotalPrice            = bill.GetTotalPrice();
                reportRevenue             += bill.TotalPrice;
                reportRoom += 1;
                //var timeSpan = bill.CardBookRoom.GetTimeSpan();
                var timeSpan = bill.CardBookRoom.DateReturnRoom - bill.CardBookRoom.DateBookRoom;
                reportTime += timeSpan.TotalHours;
            }

            string money = reportRevenue.ToString();

            /*string.Format("{0:#.00}", Convert.ToDecimal(money) / 100);*/

            /*CultureInfo cul = CultureInfo.GetCultureInfo("vi-VN");   // try with "en-US"
             * string moneyFormatVN= double.Parse(money).ToString("#,###", cul.NumberFormat);*/

            RevenueLabel.Content       = FormatCurrency.FormatCurrencyVN(money) + " đ";
            RoomRentLabel.Content      = reportRoom.ToString();
            TimeRentLabel.Content      = reportTime.ToString();
            ReportListview.ItemsSource = bills;
        }