CODEWITHSUNDEEP
c#entity-framework-coreef-core-2.1
Iliyan Ivanov
Iliyan Ivanov

Reputation: 417

Include mapped table in each entity from collection

I have following tables:

public class Author
{
    public int Id { get; set; }

    [Required]
    public string Name { get; set; }

    public ICollection<Book> Books { get; set; } = new List<Book>();
}

public class Book
{
    public int Id { get; set; }

    [Required]
    public string Title { get; set; }

    public int AuthorId { get; set; }

    public Author Author { get; set; }

    public ICollection<BookBorrower> BookBorrowers { get; set; } = new List<BookBorrower>();
}

public class BookBorrower
{
    public int Id { get; set; }

    public int BookId { get; set; }

    public Book Book { get; set; }

    public int BorrowerId { get; set; }

    public Borrower Borrower { get; set; }

    public DateTime StartDate { get; set; }

    public DateTime? EndDate { get; set; }

    public bool IsBookReturned { get; set; } = false;
}

First of all I have one-to-many and many-to-many relationships. Now the question is how to include BookBorrower through the author.

I have those code

var author = await _db.Authors
            .Include(a => a.Books)
            .FirstOrDefaultAsync(a => a.Id == id);

author contains all of its book, but each book doesn't include its BookBorrowers property.

author.Books.BookBorrowers.Count // that's zero but I have enities in those table for those book.

Upvotes: 1

Views: 44

Answers (1)

DavidG
DavidG

Reputation: 118937

You need to use ThenInclude, for example:

var author = await _db.Authors
            .Include(a => a.Books)
            .ThenInclude(b => b.BookBorrowers) //Add this line
            .FirstOrDefaultAsync(a => a.Id == id);

Upvotes: 1

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