using System;
using System.Collections.Generic;

class SortedDictionaryEnumerationDemo
{
    static void Main()
    {
          //Creates new SortedDictionary
        var dict = new SortedDictionary();
        dict.Add(4, "Four");
        dict.Add(5, "Five");
        dict.Add(1, "One");
        dict.Add(3, "Three");
        dict.Add(2, "Two");

          //Enumerating Items
        Console.WriteLine("== Enumerating Items ==");
        foreach (var item in dict)
        {
            Console.WriteLine("{0} => {1}", item.Key, item.Value);
        }

          //Enumerating Keys
        Console.WriteLine("\n== Enumerating Keys ==");
        foreach (int key in dict.Keys)
        {
            Console.WriteLine("{0} => {1}", key, dict[key]);
        }

          //Enumerating Values
        Console.WriteLine("\n== Enumerating Values ==");
        foreach (string value in dict.Values)
        {
            Console.WriteLine("{0} => {1}", value, GetKeyFromValue(dict, value));
        }
    }
     
    //Help method for Enumerating Values
    static int GetKeyFromValue(SortedDictionary dict, string value)
    {
        // Use LINQ to do a reverse dictionary lookup.
        try
        {
            return
                (from item in dict
                 where item.Value.Equals(value)
                 select item.Key).First();
        }
        catch (InvalidOperationException e)
        {
            return -1;
        }
    }

}

//Console: 
/*
== Enumerating Items ==
1 => One
2 => Two
3 => Three
4 => Four
5 => Five

== Enumerating Keys ==
1 => One
2 => Two
3 => Three
4 => Four
5 => Five

== Enumerating Values ==
One => 1
Two => 2
Three => 3
Four => 4
Five => 5
*/