entity-framework - 如何发布到OData WebAPI中的相关集合

我找到了这个answer，它帮助我设置了一条路线，但是在将实体添加到相关集合中时遇到问题。

楷模:

public class Book
{
    public int BookId { get; set; }
    public string Title { get; set; } and so on

    [ForeignKey("AuthorId")]
    public ICollection<Author> Authors { get; set; }
}

public class Author
{
    public int AuthorId { get; set; }
    public string Name { get; set; }

    [ForeignKey("BookId")]
    public ICollection<Book> Books { get; set; }
}

用于发布到相关集合的 Controller 方法:

    [ODataRoute("Books({key})/Authors")]
    public async Task<IHttpActionResult> PostAuthor([FromODataUri] int key, Author author)
    {
        var book = await db.Books.FindAsync(key);
        if (book == null)
        {
            return NotFound();
        }
        book.Authors.Add(author);

        await db.SaveChangesAsync();
        return StatusCode(HttpStatusCode.NoContent);
    }

我可以看到作者是通过发送的，但是book.Authors为空，您不能添加它。
link to image

最佳答案

查找不会带回孩子。尝试:

var book = await db.Books
                    .Include(b => b.Authors)
                    .FirstOrDefaultAsync(b => b.BookId == key);

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