c# - MVC ASP 3 表连接然后显示结果

Question

对于一个项目，我正在展示要添加到购物篮的书籍。我需要连接 3 个表才能显示可用的格式:我这样做:Books 到 bookID 上的 BookFormats，然后 BookFormats 到 formatID 上的 Format。这是一个预先布局的数据库，我无法更改。我编写了一个 LINQ 查询来显示所有这些，并创建了一个具有所有 3 个属性的 View 模型。

linq 查询:

        IEnumerable<BookAndFormatViewModel> IEBooksRepository.GetAllBooksWithFormats()
    {
        var query =
            from book in eBooks.Books
            join format in eBooks.BookFormats on book.BookID equals format.BookID
            join formatName in eBooks.Formats on format.FormatID equals formatName.FormatID
            select new BookAndFormatViewModel();
        return query.ToList();

三者的 View 模型:

    public int BookID { get; set; }
    public string ReferenceNumber { get; set; }
    public string Title { get; set; }
    public decimal Price { get; set; }
    public int FormatID { get; set; }
    public string FormatType { get; set; }

Controller 代码:

        IEnumerable<BookModel> books = repository.GetAllBooks();
        IEnumerable<BookAndFormatViewModel> booksWithFormat = repository.GetAllBooksWithFormats();

        if (books.Count() == 0)
        {
            return PartialView("NoBooks");

        }
        return PartialView("Books", booksWithFormat);   

当我运行它时，它显示空数据，只有 0 和空字段。

Answer 1

最终的解决方法是更改​​模型的构造函数，然后像这样创建模型:

            var query =
            from book in eBooks.Books
            join format in eBooks.BookFormats on book.BookID equals format.BookID
            join formatName in eBooks.Formats on format.FormatID equals formatName.FormatID
            select new BookAndFormatViewModel
            {
                BookID = book.BookID,
                ReferenceNumber = book.ReferenceNumber,
                Title = book.Title,
                Price = book.Price,
                FormatID = format.FormatID,
                FormatType = formatName.FormatType
            };