如何設置導航屬性

Question

我正在嘗試在MVC4中設置一個簡單的庫應用程序

我有以下實體

public class Book
{
    public Book()
    {
        BorrowedBooks = new List<BorrowedBooks>();

    }
    public int Id { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }        
    public virtual ICollection<BorrowedBooks> BorrowedBooks { get; set; }
}
 public class Borrower
{
    public Borrower()
    {
        BorrowedBooks = new List<BorrowedBooks>();
    }
    public int Id { get; set; }
    public string Firstname { get; set; }
    public string Lastname { get; set; }


    public virtual ICollection<BorrowedBooks> BorrowedBooks { get; set; }
}
 public class BorrowedBooks
{
    public int Id { get; set; }
    public int BookId { get; set; }
    public int BorrowerId { get; set; }
    public DateTime DateBorrowed { get; set; }

    public virtual Book Book { get; set; }
    public virtual Borrower Borrower { get; set; }

}

我有2個資料庫

 public class BookRepository : IBookRepository
    {
        private List<Book> books = new List<Book>
            {
                new Book { Id = 1, Title = "Queen of the road", Author = "Tricia Stringer", BorrowedBooks = new List<BorrowedBooks>{  new BorrowedBooks {BookId = 1, BorrowerId = 1, DateBorrowed = DateTime.Parse("26/03/2014")}} },
                new Book { Id = 2, Title = "Don't look now", Author = "Paul Jennings" },
                new Book { Id = 3, Title = "Too bold to die", Author = "Ian McPhedran" },
                new Book { Id = 4, Title = "The rosie project", Author = "Graeme Simson" },
                new Book { Id = 5, Title = "In great spirits", Author = "Archie Barwick" },
                new Book { Id = 6, Title = "The vale girl", Author = "Nelika Mcdonald" },
                new Book { Id = 7, Title = "Watching you", Author = "Michael Robotham" },
                new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" },
            };

        private List<BorrowedBooks> borrowedBooks = new List<BorrowedBooks>
            {
                new BorrowedBooks {BookId = 8, Book = new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" },   BorrowerId = 2,  DateBorrowed = DateTime.Parse("01/04/2014")},
                new BorrowedBooks {BookId = 6, BorrowerId = 4, DateBorrowed = DateTime.Parse("08/04/2014")},
                new BorrowedBooks {BookId = 2, BorrowerId = 4, DateBorrowed = DateTime.Parse("08/04/2014")},
                new BorrowedBooks {BookId = 1, BorrowerId = 1, DateBorrowed = DateTime.Parse("26/03/2014")},

            };

        public IEnumerable<Book> Search()
        {

            return books;

        }

    }



public class BorrowerRepository : IBorrowerRepository
    {
        private List<Borrower> borrowers = new List<Borrower>
            {
                new Borrower { Id = 1, Firstname = "John", Lastname = "Smith" },
                new Borrower { Id = 2, Firstname = "Mary", Lastname = "Jane" },
                new Borrower { Id = 3, Firstname = "Peter", Lastname = "Parker" },
                new Borrower { Id = 4, Firstname = "Eddie", Lastname = "Brock" },
            };


        public void Add(Borrower borrower)
        {
            this.borrowers.Add(borrower);
        }
    }

如何將屬性鏈接在一起？ 即在我的BorrowerRepository搜索方法中，它返回所有數據，但是Book值只是一個ID，如何將其與book倉庫中的值鏈接？

我的導航屬性設置有誤嗎？ 還是我設置存儲庫數據的方式？

Answer 1

一種實現方法是添加一個靜態類以將數據集合保存在內存中。 然后，在每個存儲庫中，將與數據相關的任何操作委派給數據存儲中的相應集合，然后可以使用Linq進行查詢。

 public static class DataStore
{
    private static List<Book> books = new List<Book>
        {
            new Book { Id = 1, Title = "Queen of the road", Author = "Tricia Stringer", BorrowedBooks = new List<BorrowedBooks>{  new BorrowedBooks {BookId = 1, BorrowerId = 1, DateBorrowed = DateTime.Parse("26/03/2014")}} },
            new Book { Id = 2, Title = "Don't look now", Author = "Paul Jennings" },
            new Book { Id = 3, Title = "Too bold to die", Author = "Ian McPhedran" },
            new Book { Id = 4, Title = "The rosie project", Author = "Graeme Simson" },
            new Book { Id = 5, Title = "In great spirits", Author = "Archie Barwick" },
            new Book { Id = 6, Title = "The vale girl", Author = "Nelika Mcdonald" },
            new Book { Id = 7, Title = "Watching you", Author = "Michael Robotham" },
            new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" },
        };

    private static List<BorrowedBooks> borrowedBooks = new List<BorrowedBooks>
        {
            new BorrowedBooks {BookId = 8, Book = new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" },   BorrowerId = 2,  DateBorrowed = DateTime.Parse("01/04/2014")},
            new BorrowedBooks {BookId = 6, BorrowerId = 4, DateBorrowed = DateTime.Parse("08/04/2014")},
            new BorrowedBooks {BookId = 2, BorrowerId = 4, DateBorrowed = DateTime.Parse("08/04/2014")},
            new BorrowedBooks {BookId = 1, BorrowerId = 1, DateBorrowed = DateTime.Parse("26/03/2014")},

        };

    private static List<Borrower> borrowers = new List<Borrower>
        {
            new Borrower { Id = 1, Firstname = "John", Lastname = "Smith" },
            new Borrower { Id = 2, Firstname = "Mary", Lastname = "Jane" },
            new Borrower { Id = 3, Firstname = "Peter", Lastname = "Parker" },
            new Borrower { Id = 4, Firstname = "Eddie", Lastname = "Brock" },
        };

    public static List<Book> Books { get { return books; } }
    public static List<BorrowedBooks> BorrowedBooks { get { return borrowedBooks; } }
    public static List<Borrower> Borrowers { get { return borrowers; } }
}

public class BookRepository : IBookRepository
{
    public IEnumerable<Book> Search()
    {

        return DataStore.Books.Where (b => b.Author == "Paul Jennings");
    }
}

public class BorrowerRepository : IBorrowerRepository
{
    public void Add(Borrower borrower)
    {
        DataStore.Borrowers.Add(borrower);
    }
}