I recently needed to use a function whose parameters where Enumerators. And i needed to convert string to Enum for this purpose.Eventually it turned out to be very easy. This is how i did it.
I converted the string to a Enum object using the Enum.Prase() Function.
net.webservicex.www.CurrencyConvertor objCurrencyConvertor =
new net.webservicex.www.CurrencyConvertor();
this._rate = objCurrencyConvertor.ConversionRate((net.webservicex.www.Currency)(Enum.Parse(typeof (net.webservicex.www.Currency),this._fromCurrency)),(net.webservicex.www.Currency)(Enum.Parse(typeof( net.webservicex.www.Currency),this._toCurrency)));
Here "ConversionRate" is the Function and "net.webservicex.www.Currency" is the enumertor that need to passed as the arguement.