using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

​

public class Program

{

    public static void Main()

    {

        Dictionary<string, Book> books = new Dictionary<string, Book>();

        books.Add("Joe", new Book("Essential C# 4.0", 2013));

        books.Add("Jane", new Book("Visual C Sharp 2012 Step by Step", 2014));

        books.Add("Mindy", new Book("Professional C 2012 and .NET 4.5", 2014));

        foreach (var book in books)

            Console.WriteLine(book.ToString());

        foreach (var book in books)

            Console.WriteLine(book.Value);

​

        foreach (var book in books)

            Console.WriteLine(book.Key);

        // looking up items

        Book book1 = books["Joe"];

        // contains key

        books.ContainsKey("Joe");

        // replace value

        books["Joe"] = new Book("How to Code", 2012);

        foreach (var book in books)

            Console.WriteLine(book.ToString());

    }

}

​

public class Book

{

    public string Name {get; set;}

​

    public int Year {get;set;}

​

    public Book(string Name, int Year)

    {

        this.Name = Name;

        this.Year = Year;

    }

​

    public override string ToString()

    {

        return string.Format("{0} {1}", this.Name, this.Year);

    }

}