For a project, I'm displaying books for adding to basket. I need to join 3 tables in order to show the formats available: I do: Books to BookFormats on bookID, then BookFormats to Format on formatID. This is a prelaid out database which i cannot change. I wrote a LINQ query to display them all and made a view model with the properties of all 3.
对于一个项目,我正在展示用于添加到篮子的书籍。我需要加入3个表来显示可用的格式:我这样做:BookID到bookID上的BookFormats,然后在formatID上将BookFormats格式化为格式。这是一个预先输出的数据库,我无法改变。我写了一个LINQ查询来显示它们并创建了一个具有所有3属性的视图模型。
The linq query:
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();
The view model for the three:
三者的视图模型:
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; }
The controller code:
控制器代码:
IEnumerable<BookModel> books = repository.GetAllBooks();
IEnumerable<BookAndFormatViewModel> booksWithFormat = repository.GetAllBooksWithFormats();
if (books.Count() == 0)
{
return PartialView("NoBooks");
}
return PartialView("Books", booksWithFormat);
When I run it it displays empty data just 0's and null fields.
当我运行它时,它只显示0和空字段的空数据。
1 个解决方案
#1
0
The fix in the end was to change the constructor of the model and then create the model like so:
最后的修复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
};
#1
0
The fix in the end was to change the constructor of the model and then create the model like so:
最后的修复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
};