我正在构建一个没有持久性数据的应用。所以它将在记忆中。
我有以下POCO实体
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; }
}
我创建了一个将填充一些示例数据的类
public class DemoData
{
static Book book1 = new Book { Id = 1, Title = "Queen of the road", Author = "Tricia Stringer" };
static Book book2 = new Book { Id = 2, Title = "Don't look now", Author = "Paul Jennings" };
static Book book3 = new Book { Id = 3, Title = "Too bold to die", Author = "Ian McPhedran" };
static Book book4 = new Book { Id = 4, Title = "The rosie project", Author = "Graeme Simson" };
static Book book5 = new Book { Id = 5, Title = "In great spirits", Author = "Archie Barwick" };
static Book book6 = new Book { Id = 6, Title = "The vale girl", Author = "Nelika Mcdonald" };
static Book book7 = new Book { Id = 7, Title = "Watching you", Author = "Michael Robotham" };
static Book book8 = new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" };
static Borrower borrower1 = new Borrower { Id = 1, Firstname = "John", Lastname = "Smith" };
static Borrower borrower2 = new Borrower { Id = 2, Firstname = "Mary", Lastname = "Jane" };
static Borrower borrower3 = new Borrower { Id = 3, Firstname = "Peter", Lastname = "Parker" };
static Borrower borrower4 = new Borrower { Id = 4, Firstname = "Eddie", Lastname = "Brock" };
static BorrowedBooks borrowed1 = new BorrowedBooks { BookId = 8, Book = book8, BorrowerId = 2, Borrower=borrower2, DateBorrowed = DateTime.Parse("01/04/2014") };
static BorrowedBooks borrowed2 = new BorrowedBooks {BookId = 6, Book = book6, BorrowerId = 4, Borrower = borrower4, DateBorrowed = DateTime.Parse("08/04/2014")};
static BorrowedBooks borrowed3 = new BorrowedBooks { BookId = 2, Book = book2, BorrowerId = 4, Borrower = borrower4, DateBorrowed = DateTime.Parse("08/04/2014") };
static BorrowedBooks borrowed4 = new BorrowedBooks { BookId = 1, Book = book1, BorrowerId = 1, Borrower = borrower1, DateBorrowed = DateTime.Parse("26/03/2014") };
public List<BorrowedBooks> borrowedBooks = new List<BorrowedBooks>
{
borrowed1, borrowed2, borrowed3, borrowed4
};
public List<Book> books = new List<Book>
{
book1, book2, book3, book4, book5, book6, book7, book8
};
private List<Borrower> borrowers = new List<Borrower>
{
borrower1, borrower2, borrower3, borrower4
};
}
数据访问代码
public class BookRepository : IBookRepository
{
private DemoData data = new DemoData();
public bool Add(Book book)
{
try
{
this.data.books.Add(book);
}
catch (Exception ex)
{
return false;
}
return true;
}
public bool BorrowBook(BorrowedBooks details)
{
try
{
this.data.borrowedBooks.Add(details);
}
catch (Exception ex)
{
return false;
}
return true;
}
public IEnumerable<Book> Search()
{
return data.books;
}
}
控制器代码
public class BookController : Controller
{
private IBookRepository _bookRepo;
public BookController(IBookRepository bookRepo)
{
_bookRepo = bookRepo;
}
public ActionResult Search()
{
var test = _bookRepo.Search();
return View(test);
}
}
但是当我从存储库中获取数据时，导航属性是空的......我做错了什么？
答案 0 :(得分：1)
您需要在DemoData中填写图书集。如果您没有自己设置它们，则它们为空。所以简而言之，如果你不使用任何持久性框架，你必须从双方创建关系。
例如，对于book1，您需要添加：
book1.BorrowedBooks.Add(borrowed4);
依此类推内存数据库中所有实体的所有集合。
答案 1 :(得分：0)
我认为您还需要在DemoData类中使列表静态，并从您的存储库中删除DemoData的实例私有成员。这样，所有存储库都将使用相同的数据。
public static class DemoData
{
static Book book1 = new Book { Id = 1, Title = "Queen of the road", Author = "Tricia Stringer" };
static Book book2 = new Book { Id = 2, Title = "Don't look now", Author = "Paul Jennings" };
static Book book3 = new Book { Id = 3, Title = "Too bold to die", Author = "Ian McPhedran" };
static Book book4 = new Book { Id = 4, Title = "The rosie project", Author = "Graeme Simson" };
static Book book5 = new Book { Id = 5, Title = "In great spirits", Author = "Archie Barwick" };
static Book book6 = new Book { Id = 6, Title = "The vale girl", Author = "Nelika Mcdonald" };
static Book book7 = new Book { Id = 7, Title = "Watching you", Author = "Michael Robotham" };
static Book book8 = new Book { Id = 8, Title = "Stillways", Author = "Steve Bisley" };
static Borrower borrower1 = new Borrower { Id = 1, Firstname = "John", Lastname = "Smith" };
static Borrower borrower2 = new Borrower { Id = 2, Firstname = "Mary", Lastname = "Jane" };
static Borrower borrower3 = new Borrower { Id = 3, Firstname = "Peter", Lastname = "Parker" };
static Borrower borrower4 = new Borrower { Id = 4, Firstname = "Eddie", Lastname = "Brock" };
static BorrowedBooks borrowed1 = new BorrowedBooks { BookId = 8, Book = book8, BorrowerId = 2, Borrower=borrower2, DateBorrowed = DateTime.Parse("01/04/2014") };
static BorrowedBooks borrowed2 = new BorrowedBooks {BookId = 6, Book = book6, BorrowerId = 4, Borrower = borrower4, DateBorrowed = DateTime.Parse("08/04/2014")};
static BorrowedBooks borrowed3 = new BorrowedBooks { BookId = 2, Book = book2, BorrowerId = 4, Borrower = borrower4, DateBorrowed = DateTime.Parse("08/04/2014") };
static BorrowedBooks borrowed4 = new BorrowedBooks { BookId = 1, Book = book1, BorrowerId = 1, Borrower = borrower1, DateBorrowed = DateTime.Parse("26/03/2014") };
public static List<BorrowedBooks> borrowedBooks = new List<BorrowedBooks>
{
borrowed1, borrowed2, borrowed3, borrowed4
};
public static List<Book> books = new List<Book>
{
book1, book2, book3, book4, book5, book6, book7, book8
};
private static List<Borrower> borrowers = new List<Borrower>
{
borrower1, borrower2, borrower3, borrower4
};
}
然后在您的图书库中，您可以通过静态成员而不是实例字段进行访问。
public class BookRepository : IBookRepository
{
public bool Add(Book book)
{
try
{
DemoData.books.Add(book);
}
catch (Exception ex)
{
return false;
}
return true;
}
public bool BorrowBook(BorrowedBooks details)
{
try
{
DemoData.borrowedBooks.Add(details);
}
catch (Exception ex)
{
return false;
}
return true;