OrderBy由另一個集合列表

Question

有一些問題。 需要使用其它的收集對列表進行排序：

List<Books> b = new List<Books>(); 

類書籍：

public partial class Books 
{ 
    public Books() 
    { 
     this.BookAuthors = new HashSet<BookAuthors>(); 
    } 

    public int BookID { get; set; } 
    public string BookName { get; set; } 

    public virtual ICollection<BookAuthors> BookAuthors { get; set; } 
} 

類BookAuthors：

public partial class BookAuthors 
{ 
    public int Id { get; set; } 
    public int AuthorID { get; set; } 
    public int BookID { get; set; } 

    public virtual Books Books { get; set; } 
    public virtual Authors Authors { get; set; } 
} 

類作者：

public partial class Authors 
{ 
    public Authors() 
    { 
     this.BookAuthors = new HashSet<BookAuthors>(); 
    } 

    public int AuthorID { get; set; } 
    public string FirstName { get; set; } 
    public string LastName { get; set; } 

    public virtual ICollection<BookAuthors> BookAuthors { get; set; } 
} 

我怎麼能分類b由作者姓氏？

Answer 1

這樣的事情，但如果是包含多個作者仍然您訂購該作者通過一個問題：

var sorted = 
    from book in b 
    let firstAuthor = book.BookAuthors.First() 
    let lastName = firstAuthor.LastName 
    order book by lastName 
    select book 

另外，您可以應用一些邏輯（如果你有話）......

var sorted = 
    from book in b 
    let author = book.BookAuthors.FirstOrDefault(a=>a.Primary) ?? 
     book.BookAuthors.FirstOrDefault(a=>a.Editor) ?? 
     book.BookAuthors.First() 
    let lastName = author.LastName 
    order book by lastName 
    select book