System.Xml.Xsl.Runtime.XsltConvert.ToDouble C# (CSharp) Method

        public static double ToDouble(IList<XPathItem> listItems) {
            XsltLibrary.CheckXsltValue(listItems);

            if (listItems.Count == 0)
                return Double.NaN;

            return ToDouble(listItems[0]);
        }

 private static bool CompareValues(ComparisonOperator op, XPathItem left, XPathItem right, TypeCode compType)
 {
     if (compType == TypeCode.Double)
     {
         return(CompareNumbers(op, XsltConvert.ToDouble(left), XsltConvert.ToDouble(right)));
     }
     else
     {
         Debug.Assert(op == ComparisonOperator.Eq || op == ComparisonOperator.Ne);
         if (compType == TypeCode.String)
         {
             return((XsltConvert.ToString(left) == XsltConvert.ToString(right)) == (op == ComparisonOperator.Eq));
         }
         else
         {
             Debug.Assert(compType == TypeCode.Boolean);
             return((XsltConvert.ToBoolean(left) == XsltConvert.ToBoolean(right)) == (op == ComparisonOperator.Eq));
         }
     }
 }