using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main(string[] args)

    {

        var dictionary = new Dictionary<string, CompassDirection?>

        {

            { "Foo", CompassDirection.North },

            { "Bar", null },

            { "Baz", CompassDirection.West }

        };

        Console.WriteLine("New Dictionary 1:");

        Dictionary<string, CompassDirection> newDictionary1 = dictionary

            .Where(entry => entry.Value.HasValue)

            .ToDictionary(e => e.Key, e => e.Value.Value);

        newDictionary1.Keys.ToList().ForEach(key => Console.WriteLine("Key: {0} Value: {1}", key, dictionary[key]));

        Console.WriteLine();

​

        Console.WriteLine("New Dictionary 2:");     

        Dictionary<string, CompassDirection> newDictionary2 = new Dictionary<string, CompassDirection>();

        foreach (String key in dictionary.Keys)

        {

            if (dictionary[key].HasValue)

            {

                newDictionary2.Add(key, dictionary[key].Value);

            }

        }

        newDictionary2.Keys.ToList().ForEach(key => Console.WriteLine("Key: {0} Value: {1}", key, dictionary[key]));

    }

}

​

public enum CompassDirection

{

    North, East, South, West

}