public void LoadCurrencies(List <CurrencyData> list)
{
if (list is null)
{
return;
}
foreach (var c in list)
{
if (Currencies.Contains(c.ID))
{
continue;
}
Currencies.Add(c.ID);
}
}
//calculate exchanged rate
public double CalculateExchangedRate(string currencyCross, string currency, double amount)
{
#region CalculateExchangedRate sanity
//throw exception if currencyCross is empty,
//whitespace, or otherwise not 6 characters
if (String.IsNullOrWhiteSpace(currencyCross) || currency.Length != 6)
{
throw new ArgumentException("Currency cross must be exactly six characters.");
}
//throw exception if currencyCross does not match an entry in CurrencyCrosses
if (!CurrencyCrosses.Contains(currencyCross))
{
throw new ArgumentException("Given currency cross does not exist.");
}
//throw exception if currency does not match an entry in Currencies
if (!Currencies.Contains(currency))
{
throw new ArgumentException("Given currency does not exist.");
}
//throw exception if there is no exchange rate for currencyCross
if (!ExchangeRates.ContainsKey(currencyCross))
{
throw new ArgumentException("Given currency cross does not have a specified exchange rate.");
}
//throw exception if amount is not positive
if (amount <= 0)
{
throw new ArgumentException("Amount must be positive.");
}
#endregion
double rate = ExchangeRates[currencyCross];
if (currencyCross.Substring(0, 3) == currency) //if they want the first currency of the cross currency (AAA from AAABBB),
{
amount *= rate; //multiply amount by rate
return(amount); //and return amount
}
else //ELSE
{
double reverseRate = 1 / rate; //reverse the rate (if 1 AAA = 6.50 BBB, 1 BBB = 1 / 6.50 = 0.15 AAA),
amount *= reverseRate; //multiply amount by reversed rate,
return(amount); //and return amount
}
}
