public string TotalPrice(string basePrice, string discountIndicator, string stateTax, string quantity) { double _basePrice; int _quantity; bool _discountIndicator; double _taxableAmount; //if state is not selected - request for selection if (string.IsNullOrWhiteSpace(stateTax)) { return("<B>Please select state<B>"); } double.TryParse(basePrice, out _basePrice); Int32.TryParse(quantity, out _quantity); bool.TryParse(discountIndicator, out _discountIndicator); _taxableAmount = _quantity * _basePrice; if (_discountIndicator) { _taxableAmount = _taxableAmount - (_taxableAmount * 0.1); } IPriceCalculator priceCalculator = _processLocator.GetProcessor <IPriceCalculator>(stateTax); return("Your Total Price will be : " + "<b> $" + priceCalculator.PriceWithTax(_taxableAmount).ToString() + "<b>"); }