/// <summary>
/// Gets the best (latest) exchange rate for a pair of currencies from a table of rates.
/// </summary>
/// <param name="ADailyRateTable">A table of rates that has been obtained by calling LoadExchangeRateData for a period of interest.</param>
/// <param name="ACurrencyFrom">The 'from' currency</param>
/// <param name="ACurrencyTo">The 'to' currency</param>
/// <param name="AEnforceUniqueRate">If true the method will only return true if there is a unique rate for the specified currencies on the 'latest' date.
/// If false the method returns the rate for the latest 'time' on the latest date.</param>
/// <param name="ARateOfExchange">The returned rate</param>
/// <param name="AEffectiveDate">The date associated with the returned rate.</param>
/// <returns>True if a matching rate was found. The rate and date are in the out parameters.</returns>
public static bool GetBestExchangeRate(ExchangeRateTDSADailyExchangeRateTable ADailyRateTable,
string ACurrencyFrom,
string ACurrencyTo,
Boolean AEnforceUniqueRate,
out decimal ARateOfExchange,
out DateTime AEffectiveDate)
{
ARateOfExchange = 0.0m;
AEffectiveDate = DateTime.MinValue;
ADailyExchangeRateRow uniqueFittingRow = null;
bool oppositeRate = false;
// sort rates by date, look for rate just before the date we are looking for
string rowFilter = String.Format("{0}='{1}' AND {2}='{3}'",
ADailyExchangeRateTable.GetFromCurrencyCodeDBName(),
ACurrencyFrom,
ADailyExchangeRateTable.GetToCurrencyCodeDBName(),
ACurrencyTo);
ADailyRateTable.DefaultView.RowFilter = rowFilter;
ADailyRateTable.DefaultView.Sort = String.Format("{0} DESC, {1} DESC",
ADailyExchangeRateTable.GetDateEffectiveFromDBName(),
ADailyExchangeRateTable.GetTimeEffectiveFromDBName());
// If we are after a unique row we need to remember the one from this view, if it exists
if (AEnforceUniqueRate && (ADailyRateTable.DefaultView.Count == 1))
{
uniqueFittingRow = (ADailyExchangeRateRow)ADailyRateTable.DefaultView[0].Row;
}
if ((ADailyRateTable.DefaultView.Count == 0) || AEnforceUniqueRate)
{
// try other way round
rowFilter = String.Format("{0}='{1}' AND {2}='{3}'",
ADailyExchangeRateTable.GetToCurrencyCodeDBName(),
ACurrencyFrom,
ADailyExchangeRateTable.GetFromCurrencyCodeDBName(),
ACurrencyTo);
ADailyRateTable.DefaultView.RowFilter = rowFilter;
oppositeRate = true;
if (AEnforceUniqueRate)
{
if (ADailyRateTable.DefaultView.Count > 1)
{
// This way round does not have a unique rate
uniqueFittingRow = null;
}
else if ((ADailyRateTable.DefaultView.Count == 1) && (uniqueFittingRow == null))
{
// we will use this as our unique rate
uniqueFittingRow = (ADailyExchangeRateRow)ADailyRateTable.DefaultView[0].Row;
}
else
{
// put this variable back as it was
oppositeRate = false;
}
}
}
ADailyExchangeRateRow fittingRate = null;
if (AEnforceUniqueRate)
{
// Did we get a unique rate?
if (uniqueFittingRow != null)
{
fittingRate = uniqueFittingRow;
}
}
else if (ADailyRateTable.DefaultView.Count > 0)
{
// Just return the first in the list
fittingRate = (ADailyExchangeRateRow)ADailyRateTable.DefaultView[0].Row;
}
if (fittingRate != null)
{
if (oppositeRate)
{
ARateOfExchange = GLRoutines.Divide(1.0m, fittingRate.RateOfExchange);
}
else
{
ARateOfExchange = fittingRate.RateOfExchange;
}
AEffectiveDate = fittingRate.DateEffectiveFrom;
}
//Returning 0 causes a validation error to force the user to select an exchange rate:
return(ARateOfExchange != 0.0m);
}
/// <summary>
/// Calculate Tax-Deductible Amount and Non-Deductible Amount for a gift amount using the tax deductible percentage
/// </summary>
/// <param name="ATaxDeductAmount"></param>
/// <param name="ANonDeductAmount"></param>
/// <param name="AGiftAmount"></param>
/// <param name="ADeductiblePercentage"></param>
private static void CalculateTaxDeductibilityAmounts(
out decimal ATaxDeductAmount, out decimal ANonDeductAmount, decimal AGiftAmount, decimal ADeductiblePercentage)
{
ATaxDeductAmount = GLRoutines.Divide(AGiftAmount * ADeductiblePercentage, 100, 2);
ANonDeductAmount = AGiftAmount - ATaxDeductAmount;
}
