That's plain ugly. Is it needed? Probably not. And what the heck is this Functions class? That's VERY much and anti-pattern and non-standard. Lots and lots of code that needs to be maintained just to check and pass parameters is very poor code.

Another book I highly recommend is Brownfield Development in .Net. It talks about how to effectively refactor existing code and make it better. I rate it as one of the best tech books I've ever read. But you still need to understand refactoring and patterns.

Speaking of anti-patterns. //TODO: is one of them.

>The parameters are passed as XML string. This is the typical method and I am following the pattern which was developed before me:
>
>This is part of the code of the method I wrote today and unit testing right now
>
>

>internal static String GetGuestActivity(Dictionary<String, String> parameters)
>        {
>            Logging.Log(1, "Entering GetGuestActivity");
>
>            List<String> requiredParameters = new List<String>() { "tnGuestNo", "ttStartDate", "ttEndDate" };
>            //always required parameters (but not used)          { "tcSalesPoint", "tcOperator" };
>            //optional parameters                                { "tcFilter"};
>            
>            //TODO: get rid of not used tcFilter parameter in the code and SP
>
>            HashSet<String> availableReturnTypes = new HashSet<String>(StringComparer.OrdinalIgnoreCase) { "STR", "ADO", "XML", "XM2" };
>
>            String messageText = "";
>            Int32 errorValue = 0;
>            Int32 statusCode = 0;
>
>            // If all necessary parameters are present and valid, proceed...
>            if (Functions.CheckRequiredParameters(parameters, requiredParameters, availableReturnTypes, out statusCode, out messageText))
>            {
>                // Parse out the parameters
>                String tcGuestNo = Functions.GetParameterValue(parameters, "tnGuestNo");
>                String tcStartDate = Functions.GetParameterValue(parameters, "ttStartDate");
>                String tcEndDate = Functions.GetParameterValue(parameters, "ttEndDate");
>                String tcFilter = Functions.GetParameterValue(parameters, "tcFilter");
>
>                Decimal guestNo;
>
>                if (!Decimal.TryParse(tcGuestNo, out guestNo) || 0 == guestNo)
>                {
>                    statusCode = 999;
>                    messageText = "tnGuestNo expression can not be zero";
>                    return Base.LogAndReturnResult(errorValue, statusCode, messageText);
>                }

>
>UPDATE. I changed this method to use only 1 exit point as it has only 2 exit points, so it was relatively easy to convert.