Question

In C# 4.0 (or earlier if it can be done), how does a parent class pass a reference of itself to a child class. For example:

class Book
{

    public string bookname = "a";
    public static List<Page> pages = new List<Page>();

    static void Main(string[] args)
    {
        Page pageone = new Page("one");
        pages.Add(new Page("one"));
    }
}
public class Page
{
    Book book;
    public Page(string pagetitle)
    {
        Console.WriteLine(pagetitle);
        Console.WriteLine("I'm from bookname :?");
    }
}

How can I get Page to recognize which book it’s in? I’m trying to pass the Book class in the constructor, but don’t know how.

Answer 1

You’re having trouble because you’ve made your book class the entry point for your application, which means you don’t have an actual Book instance.

Try something like this instead:

public class Program
{
    static void Main(string[] args)
    {
        Book book1 = new Book();
        book1.AddPage("one");   
    }
}

public class Book
{
    public string Bookname = "a";
    public List<Page> Pages = new List<Page>();

    public void AddPage(string pageTitle)
    {
        Pages.Add(new Page(this, pageTitle));
    }
}

public class Page
{
    Book book;
    public Page(Book b, string pagetitle)
    {
        book = b;
        Console.WriteLine(pagetitle);
        Console.WriteLine("I'm from book '{0}'.", book.Bookname);
    }
}