Question

有一些问题。需要按另一个集合对列表进行排序：

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

课本：

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; }
}

Class 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; }
}

班级作者：

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; }
}

我如何按作者姓氏排序b？

Answer 1

这样的事情，虽然有多位作者，但仍然是一个问题，由你订购的作者：

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

或者你可以应用一些逻辑（如果有的话）......

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

OrderBy由另一个集合列出

1 个答案: