一旦使用Projections，就会忽略Include（..）语句

Question

我有一种方法，当我使用select子句时，（艺术家和流派）会抛出空引用异常。如果我不使用select子句，那么它就无法将 system.collections.generic.list转换为system.collections.generic.ienumerable 。

 public ActionResult Attending()
 {
    var userId = User.FindFirst(ClaimTypes.NameIdentifier).Value;
    var gigs = _context.Attendances.Include(a => a.Gig.Artist).Include(a => a.Gig.Genre).Where(a => a.AttendeeId == userId).ToList();
    var viewModel = new GigsViewModel()
    {
       UpcomingGigs = gigs,
       ShowActions = User.Identity.IsAuthenticated,
       Heading = "Gigs I'm Attending"
       };
       return View("Gigs", viewModel);
    }

这是我的ViewModel：

public class GigsViewModel
{
   public IEnumerable<Gig> UpcomingGigs { get; set; }
   public bool ShowActions { get; set; }
   public string Heading { get; set; }
}

这是我的出勤班

public class Attendance
{
    public Gig Gig { get; set; }
    public ApplicationUser Attendee { get; set; }
    [Key]
    public int GigId { get; set; }
    [Key]
    public string AttendeeId { get; set; }
}