C# 我如何与linq建立多对多关系

我想问我如何才能查询每本书的类型，我尝试了很多方法，但都失败了

书籍：

使用SelectMany：

    class Program
    {
         static void Main(string[] args)
        {
            Context db = new Context();

            var results = db.Book.SelectMany(x => x.Genres.Select(y => new
            {
                id = x.Id,
                title = x.Title,
                authorId = x.Author.Id,
                authorName = x.Author.FullName,
                genreId = y.Id,
                genreName = y.Name
            })).ToList();
 

        }
    }
    public class Context
    {
        public List<Book> Book { get; set; }
        public List<Genre> Genre { get; set; }
        public List<Author> Author { get; set; }
    }
    public class Book
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public virtual ICollection<Genre> Genres { get; set; }
        public virtual Author Author { get; set; }
    }
    public class Genre
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public virtual ICollection<Book> Books { get; set; }
    }
    public class Author
    {
        public int Id { get; set; }
        public string FullName { get; set; }
        public virtual ICollection<Book> Books { get; set; }
    }
 

类程序
{
静态void Main（字符串[]参数）
{
Context db=newcontext（）；
var results=db.Book.SelectMany（x=>x.Genres.Select（y=>new
{
id=x.id，
title=x.title，
authorId=x.Author.Id，
authorName=x.Author.FullName，
genreId=y.Id，
genreName=y.Name
})).ToList（）；
}
}
公共类上下文
{
公共列表簿{get；set；}
公共列表类型{get；set；}
公共列表作者{get；set；}
}
公共课堂用书
{
公共int Id{get；set；}
公共字符串标题{get；set；}
公共虚拟ICollection类型{get；set；}
公共虚拟作者{get；set；}
}
公共课体裁
{
公共int Id{get；set；}
公共字符串名称{get；set；}
公共虚拟ICollection图书{get；set；}
}
公共类作者
{
公共int Id{get；set；}
公共字符串全名{get；set；}
公共虚拟ICollection图书{get；set；}
}

public class Genre
{
    public int Id { get; set; }
    [StringLength(32)]
    public string Name { get; set; }
    public virtual ICollection<Book> Books { get; set; }
}

public class Author
{
    public int Id { get; set; }
    public string FullName { get; set; }
    public virtual ICollection<Book> Books { get; set; }
}

from book in Books
join author in Authors on book.Author.Id equals author.Id
??join Genre ??
select new {book, author, ?list genres}

    class Program
    {
         static void Main(string[] args)
        {
            Context db = new Context();

            var results = db.Book.SelectMany(x => x.Genres.Select(y => new
            {
                id = x.Id,
                title = x.Title,
                authorId = x.Author.Id,
                authorName = x.Author.FullName,
                genreId = y.Id,
                genreName = y.Name
            })).ToList();
 

        }
    }
    public class Context
    {
        public List<Book> Book { get; set; }
        public List<Genre> Genre { get; set; }
        public List<Author> Author { get; set; }
    }
    public class Book
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public virtual ICollection<Genre> Genres { get; set; }
        public virtual Author Author { get; set; }
    }
    public class Genre
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public virtual ICollection<Book> Books { get; set; }
    }
    public class Author
    {
        public int Id { get; set; }
        public string FullName { get; set; }
        public virtual ICollection<Book> Books { get; set; }
    }