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

class Program
{
    static void Main(string[] args)
    {
        int[] keys = { 31, 28, 31, 30, 31 };
        string[] values = { "Jan", "Feb", "Mar", "Apr", "Jan" };

        var list1 = new List<KeyValuePair<int, string>>();
        var list2 = new List<Disp>();
        Console.WriteLine("テストデータ");
        for (int i = 0; i < keys.Length; i++)
        {
            list1.Add(new KeyValuePair<int, string>(keys[i], values[i]));
            list2.Add(new Disp(keys[i], values[i]));
            Console.WriteLine("{0} {1}", keys[i], values[i]);
        }

        Console.WriteLine("汎用");
        foreach (var disp in list1.OrderBy(t => -t.Key))
        {
            Console.WriteLine("{0} {1}", disp.Key, disp.Value);
        }

        Console.WriteLine("独自クラス");
        foreach (var disp in list2.OrderBy(t => -t.Key))
        {
            Console.WriteLine("{0} {1}", disp.Key, disp.Value);
        }
    }

    class Disp
    {
        public int Key { get; set; }
        public string Value { get; set; }
        public Disp(int key, string value)
        {
            Key = key;
            Value = value;
        }
    }
}