Question

I am trying to save data to ArrayList() by using following code in WinForm application. The problem is when I do this my output in bookList.txtBookList.Text is Lab_8.Book and I can’t figure out why. Hope for some tips.

BookEntry.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Collections;

namespace Lab_8
{
    public partial class BookEntry : Form
    {
        private ArrayList books = new ArrayList();
        private BookList bookList = new BookList();

        public BookEntry()
        {
            InitializeComponent();
        }

        private void btnEnter_Click(object sender, EventArgs e)
        {
            books.Add(new Book(txtTitle.Text, txtFirstName.Text, 
                txtLastName.Text, txtPublisher.Text, 
                float.Parse(txtPrice.Text)));
        }

        private void btnShowBooks_Click(object sender, EventArgs e)
        {
            foreach (object list in books)
            {
                bookList.txtBookList.Text += list.ToString() + "\n";
            }

            bookList.ShowDialog();
        }
    }
}

Book.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Lab_8
{
    class Book : Publication
    {
        private string authorFirstName, authorLastName;

        public Book()
        { }

        public Book(string title, string firstName, string lastName, string publisherName, float price)
        : base(title, publisherName, price)
        {
            this.authorFirstName = firstName;
            this.authorLastName = lastName;
        } 

        public string getAuthorName()
        {
            return authorFirstName + " " + authorLastName;
        }

        public string AuthorFirstName
        {
            get
            {
                return authorFirstName;
            }
            set
            {
                authorFirstName = value;
            }
        }
        public string AuthorLastName
        {
            get
            {
                return authorLastName;
            }
            set
            {
                authorLastName = value;
            }
        }
    }
}

Regards. HelpNeeder

Answer 1

The problem here is the Book doesn’t override ToString, which means this loop:

foreach (object list in books)
{
  bookList.txtBookList.Text += list.ToString() + "\n";
}

Will just print out the name of the class (with the namespace), or Lab_8.Book.

In order to correct this, you could override ToString() in Book:

class Book : Publication
{
   // .. Your code...

   public override string ToString()
   {
       return this.Title + " by " + this.AuthorFirstName + " " + this.AuthorLastName;
   }

That being said, I would highly recommend converting the ArrayList to use List<Book> instead. This will allow you to refer to the books as a book directly, ie:

foreach (Book book in books)
{
  bookList.txtBookList.Text += book.AuthorFirstName + Environment.NewLine;
}

The only change required for this would be to change:

private ArrayList books = new ArrayList();

To:

private List<Book> books = new List<Book>();

And then also change the list as above…