成员的完整列表，这些成员属于 CThostFtdcExchangeRateField,包括所有继承而来的类成员

BrokerID	CThostFtdcExchangeRateField
ExchangeRate	CThostFtdcExchangeRateField
FromCurrencyID	CThostFtdcExchangeRateField
FromCurrencyUnit	CThostFtdcExchangeRateField
ToCurrencyID	CThostFtdcExchangeRateField