public IActionResult Index()
        {
            var viewModel = new ShowCurrencyConverterViewModel();

            viewModel.AllCurrencies = GetAllCurrencies();
            return(View(viewModel));
        }
        public IActionResult Index(ShowCurrencyConverterViewModel model)
        {
            //if ((model.Tal % 2) == 0)
            //{
            //    ModelState.AddModelError("Tal", "Måste vara ijmt");
            //}

            if (ModelState.IsValid)
            {
                model.Result = _currentCalculator.ConvertCurrency(model.FromCurrency, model.ToCurrency, model.Belopp);
            }
            model.AllCurrencies = GetAllCurrencies();
            return(View(model));
        }