public async Task <ActionResult> ViewSalesData()
        {
            try
            {
                HttpPostedFileBase salesDataFile = Request.Files.Count > 0 ? Request.Files[0] : null;
                IList <string>     csvData       = CSVHelper.ReadCSVFile(salesDataFile);

                if (csvData == null)
                {
                    ViewBag.Errors = new[] { "Unable to read CSV file." };
                }
                IList <VehicleDetail> vehicleDetails = CSVHelper.ConvertToModel(csvData);
                ViewBag.MostSoldVehicle = vehicleDetails.GroupBy(vd => vd.Vehicle).GetHighesCountGroup();
                return(View("Results", vehicleDetails));
            }
            catch (Exception ex)
            {
                Response.StatusCode = 500;
                return(View("Error"));
            }
        }