public static string HelloWorld(string YourName)
 {
    return "Hello " + YourName;   
 }

using System;
using System.Linq;
using System.Xml.Linq;
  
public class XMLsort
{
 /*  define variables netMyfile and netOutFile as parameters */
 /*  passed into the SORT method                             */ 
 public static void Sort(string netMyFile, string netOutFile)
 {
  /* open XML from netMyFile parameter value set as {UserVar(infile)}*/ 
    XElement root = XElement.Load(netMyFile);
    var orderedtabs = root.Elements("ROW")
        .OrderByDescending(xtab => (string)xtab.Element("INVESTOR").Element("PORTFOLIONUM"))
        .ToArray();
    root.RemoveAll();
    foreach (XElement tab in orderedtabs)
        root.Add(tab);
  /* write Sorted XML to netOutFile parameter value set as {UserVar(outfile)}*/        
    root.Save(netOutFile);
 }
}