实体框架-如何过滤急切加载的导航/关系属性？

Question

我有以下实体框架4.1实体和关系

Concert ConcertId，AdministratorUserId，Name，IsDeleted

订票 BookingId，ConcertId，UserId，IsDeleted

UserId，UserId，Name，IsDeleted

Relationship音乐会1.M预订1.1用户

现在，我试图选择所有的音乐会为一个特定的AdminstratorUserId，但也包括所有的预订，每次音乐会和用户的详细信息，为每次预订。我也想应用一个过滤器，其中IsDeleted ==为每个音乐会，预订和用户的假。我想交还一份音乐会的名单，这些音乐会的预订和用户详细资料被保留为导航属性。

在SQL中，这就是我试图实现的目标：

SELECT *
FROM concert c, booking b, user u
WHERE c.ConcertId = b.ConcertId AND b.UserId = u.UserId AND c.AdministratorId = 10
AND c.IsDeleted = false AND b.IsDeleted = false AND u.IsDeleted = false

据我所知，使用"Include“方法来急切加载，不允许对加载的子实体进行过滤或子查询；它返回该联接的所有记录，因此我尝试使用匿名投影，如下所示：

int adminId = 10;

var concerts = _context.Concerts
    .Where(p => p.AdministratorId == adminId && p.IsDeleted == false)
    .Select(p => new {
        Concerts = p,
        Bookings = p.Bookings
            .Where(q => q.IsDeleted == false && q.User.IsDeleted == false)
            .Select(r => new {
                Bookings = r,
                User = r.User
            })
            .AsEnumerable()
            .Select(q => q.Bookings)
    })
    .AsEnumerable()
    .Select(p => p.Concerts)
    .ToList();

但是，这仍然是返回所有记录，而不是过滤出IsDeleted = true的记录。有人有什么想法，或建议，我如何才能清理这个可怕的问题？

我还尝试过类似于此的方法(http://blogs.msdn.com/b/alexj/archive/2009/06/02/tip-22-how-to-make-include-really-include.aspx)，它再次失败(返回所有预订，甚至删除的预订)：

var concertsQuery = (ObjectQuery<Concert>)_context.Concerts
    .Where(p => p.UserId == userId
        && p.IsDeleted == false
        && p.Bookings.Any(q => q.IsDeleted == false && q.User.IsDeleted == false)
    );

var concerts = concertsQuery.Include("Bookings").Include("Bookings.User").ToList();

Answer 1

因此，我设法解决这个问题的方法是按照Ladislav的答案运行LINQ查询，然后使用匿名对象将各个对象重新附加到它们正确的关系属性，如下所示：

var concertResult = new List<Concert>();

foreach (var concertObject in concerts)
{
    var concert = concertObject.Concert;

    foreach (var bookingObject in concertObject.Bookings)
    {
        var booking = bookingObject.Booking;
        booking.User = bookingObject.User;
        concert.Bookings.Add(booking);
    }
    concertResult.Add(concert);
}

Answer 2

去掉那些AsEnumerable，它们会将您的查询转到linq到对象：

var concerts = _context.Concerts
    .Where(p => p.AdministratorId == adminId && p.IsDeleted == false)
    .Select(p => new {
        Concerts = p,
        Bookings = p.Bookings
            .Where(q => q.IsDeleted == false && q.User.IsDeleted == false)
            .Select(r => new {
                Bookings = r,
                User = r.User
            })
    })
    .ToList();