C#

private static ArrayList books;

// Create an instance of a book and fill out it's data
Book Book1 = new Book();
Book1.iBookId = 15;
Book1.sAuthor = "George Washington";

// Add the book to the collection
books.Add(Book1);

// Create the overloaded methods to find a book
public static Book FindBook(int iBookId)
{
	// Call the private method below to find the book
	return _FindBook(iBookId, "");
}

public static Book FindBook(String sAuthor)
{
	// Call the private method below to find the book
	return _FindBook(0, sAuthor);
}

KMAROIS wrote:

I get the error "Cannot implicitly convert type 'object' to 'Book'".

I don't understand this. The object in the collection is already a book.

List<Book> books = new List<Book>();
 
private static Book Find(int bookId) 
{
  return books.FirstOrDefault(b => b.iBookId == bookId)
}

private static Book Find(string authorName) 
{
  return books.FirstOrDefault(b => String.Compare(b.sAuthor, authorName) == 0);
}

KMAROIS wrote:

Problem is, I'm stuck with VS 2003 for now

private static Book Find(int bookId) 
{
   Book foundBook = null;
 
   foreach(Book book in books)
   {
      if (book.iBookId == bookId)
      {
         foundBook = book;
         break;
      }
   }
   return foundBook;
}
 
private static Book Find(string authorName) 
{
   Book foundBook = null;
 
   foreach(Book book in books)
   {
      if (String.CompareOrdinal(book.sAuthor, authorName) == 0)
      {
         foundBook = book;
         break;
      }
   }
   return foundBook;
}

bookArrayBook = books[iBook];

bookArrayBook = (Book)books[iBook];

bookArrayBook = (Book)books[iBook];

dhaim
programming is a hobby that make some money as side effect

Dewald wrote:

Given ClassB cb = new ClassB();
Is there a difference between:
ClassA ca = cb as ClassA;
and
ClassA ca = (ClassA)cb;

Dewald wrote:

Is there a way to typecast the other way round? In other words, I have an instance of ClassA and I want to use it and view it as if it is of ClassB.

Dewald wrote:

What is the difference between "type casting" and "boxing"? The latter is a term that's new to me and I get the impression that it might be different terms for the same concept? Am I wrong?