an array of string values sorted first by length, then sorted alphabetically, using a case-insentive comparison.

   
 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class CaseInsensitiveComparer : IComparer<string> {
    public int Compare(string x, string y) {
        return string.Compare(x, y, true);
    }
}

public class MainClass {
    public static void Main() {

        string[] words = { "a", "A", "b", "B", "C", "c" };

        var sortedWords =
            words.OrderBy(a => a.Length)
                    .ThenBy(a => a, new CaseInsensitiveComparer());

        Console.Write(sortedWords);
    }
}