public double DoCalculation1(int id, string manufactur, DateTime start, DateTime end)//חישוב עלות השכרה { List <DoOrderModel> listVM = new List <DoOrderModel>(); var allCars = carsmanager.Cars.ToList(); //var carto = allCars.Where(c => c.Cartyp.Manufacturer == manufactur).Select(x => x.CarID==id).FirstOrDefault(); var carToCalculate = carsmanager.GetCarTypeByID(id); var total = (end - start).TotalDays; double CostOfRental = carToCalculate.Daily_cost * total; DoOrderModel vm = new DoOrderModel { }; //<---- return(CostOfRental); }