>Well, I tried to reply earlier but I have problems with UT :(
>
>This is a bad C# code (I wrote it in VFP before I realized this was a .net forum)
>
>

>using System;
>using System.Collections.Generic;
>using System.Linq;
>using System.Text;
>using System.Threading.Tasks;
>
>namespace RegExpTest
>{
>    class Program
>    {
>        static void Main(string[] args)
>        {
>            Console.WriteLine(ICRFormat("16Mh1234"));
>            Console.WriteLine(ICRFormat("15D35999"));
>            Console.WriteLine(ICRFormat("115D35999"));
>            Console.Read();
>        }
>
>        static String ICRFormat(String UnformattedICR)
>        {
>            System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex("^(\\d\\d)([A-Z]{1,2})(\\d{1,6})$", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
>            System.Text.RegularExpressions.MatchCollection matches = regex.Matches(UnformattedICR);
>            if (matches.Count == 1)
>            {
>                System.Text.RegularExpressions.Match match = matches[0];
>                return match.Groups[1] + " " + match.Groups[2].ToString().ToUpper() + " " + match.Groups[3];
>            }
>            return "Invalid Entry";
>        }
>    }
>}
>
>

Neat! Maybe better to make the Regex static rather than instantiating on each call. Toyed with incorporating it into a class :

   public class IEReg
    {
        static System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex("^(\\d\\d)([A-Z]{1,2})(\\d{1,6})$", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

        private string ieReg, ieCounty, ieNumber;
        private int? ieYear;

        public IEReg(string s)
        {
            System.Text.RegularExpressions.MatchCollection matches = regex.Matches(s);
            if (matches.Count == 1)
            {
                System.Text.RegularExpressions.Match match = matches[0];
                ieReg = match.Groups[1] + " " + match.Groups[2].ToString().ToUpper() + " " + match.Groups[3];
                ieYear = int.Parse(match.Groups[1].Value);
                ieCounty = match.Groups[2].Value;
                ieNumber = match.Groups[3].Value;
            }
            else { ieReg = "Invalid Entry"; }
        }
        public string ICRString { get { return ieReg; } }
        public int? Year { get { return ieYear; } }
        public string County { get { return ieCounty; } }
        public string Number { get { return ieNumber; } }
        public static IEnumerable<IEReg> Items(List<string> list) { return list.Select(x => new IEReg(x)); }
    }

which would allow:

List<string> numbers = new List<string> { "16Mh1234", "15D35999", "115D35999", "15D35123" };
            var xx = IEReg.Items(numbers).Where(x => x.Year == 15);
            //or
            IEReg.Items(numbers).OrderBy(x => x.Year).ThenBy(x => x.County).ToList().ForEach(x=>Console.WriteLine(x.ICRString));
            //etc