How create a new deep copy (clone) of a List<T>?

Question

In the following piece of code,

using System; using System.Collections.Generic; using System.Drawing; using System.Windows.Forms;  namespace clone_test_01 {      public partial class MainForm : Form     {          public class Book         {             public string title = "";              public Book(string title)             {                 this.title = title;             }         }           public MainForm()         {             InitializeComponent();              List<Book> books_1 = new List<Book>();             books_1.Add(  new Book("One")  );             books_1.Add(  new Book("Two")  );             books_1.Add(  new Book("Three")  );             books_1.Add(  new Book("Four")  );              List<Book> books_2 = new List<Book>(books_1);              books_2[0].title = "Five";             books_2[1].title = "Six";              textBox1.Text = books_1[0].title;             textBox2.Text = books_1[1].title;         }     }  } 

I use a Book object type to create a List<T> and I populate it with a few items giving them a unique title (from 'one' to 'five').

Then I create List<Book> books_2 = new List<Book>(books_1).

From this point, I know it's a clone of the list object, BUT the book objects from book_2 are still a reference from the book objects in books_1. It's proven by making changes on the two first elements of books_2, and then checking those same elements of book_1 in a TextBox.

books_1[0].title and books_2[1].title have indeed been changed to the new values of books_2[0].title and books_2[1].title.

NOW THE QUESTION

How do we create a new hard copy of a List<T>? The idea is that books_1 and books_2 become completely independent of each other.

I'm disappointed Microsoft didn't offer a neat, fast and easy solution like Ruby are doing with the clone() method.

What would be really awesome from helpers is to use my code and alter it with a workable solution so it can be compiled and work. I think it will truly help newbies trying to understand offered solutions for this issue.

EDIT: Note that the Book class could be more complex and have more properties. I tried to keep things simple.

Answer 1

You need to create new Book objects then put those in a new List:

List<Book> books_2 = books_1.Select(book => new Book(book.title)).ToList(); 

Update: Slightly simpler... List<T> has a method called ConvertAll that returns a new list:

List<Book> books_2 = books_1.ConvertAll(book => new Book(book.title));