System.DateTimeParse.GetDateTimeParseException C# (CSharp) Method

        private static Exception GetDateTimeParseException(ref DateTimeResult result) {
            switch (result.failure) {
                case ParseFailureKind.ArgumentNull:
                    return new ArgumentNullException(result.failureArgumentName, Environment.GetResourceString(result.failureMessageID));
                case ParseFailureKind.Format:
                    return new FormatException(Environment.GetResourceString(result.failureMessageID));
                case ParseFailureKind.FormatWithParameter:
                    return new FormatException(Environment.GetResourceString(result.failureMessageID, result.failureMessageFormatArgument));
                case ParseFailureKind.FormatBadDateTimeCalendar:
                    return new FormatException(Environment.GetResourceString(result.failureMessageID, result.calendar));
                default:
                    BCLDebug.Assert(false, "Unkown DateTimeParseFailure: " + result);
                    return null;

            }
        }
   }