如何过滤 IList 子查询 EF Core 2.2

Question

我有这些（简化的）模型：

public class Participant {
    public Guid Id { get; set; }
    public string Name { get; set; }
    public Guid TeamId { get; set; }
    public Team Team { get; set; }
}

public class Team {
    ...
}

public class Activity {
    public Guid Id { get; set; }
    public string Name { get; set; }
    public int Status { get; set; }
    public IList<ActivityAttendee> ActivityAttendees { get; set; }
}

public class ActivityAttendee {
    public Guid Id { get; set; }
    public Guid ActivityId { get; set; }
    public Guid ParticipantId { get; set; }
    public int Status { get; set; }
    public Participant Participant { get; set; }
}

参与者的身份是这样的：

Guid? participantId = Guid.TryParse(HttpContext.User.Claims.FirstOrDefault(c => c.Type == "Id")?.Value, out Guid tmp) ? (Guid?)tmp : null;

我这样查询活动：

var activities = await _context.Activities.Include(x => x.ActivityAttendees).ThenInclude(x => x.Participant).Where(x => x.Status == 1).AsNoTracking().ToListAsync();

现在我需要过滤参与者参加的活动。我试过：

var participantActivities = activities.Where(x => x.ActivityAttendees.ParticipantId == participantId);

var participantActivities = activities.Where(x => x.ActivityAttendees.Contains(y => x.ActivityAttendees.Where(z => z.ParticipantId == participantId)));

var participantActivities = activities.Where(x => x.ActivityAttendees.Any(y => y.ParticipantId == participantId))

我怎样才能做到这一点？

在 "normal" SQL 我会做这样的事情：

SELECT Id, Name FROM Activities WHERE Id IN (Select ActivityId FROM ActivityAttendees WHERE ParticipantId = participantId))

接下来，我还需要过滤参与者没有参加但有团队成员参加的活动（按ActivityAttendee.Participant.TeamId分组），但我认为当上述问题得到回答时我可以做到这一点.

Answer 1

正确的方法是：

var participantActivities = activities.Where(x => x.ActivityAttendees.Any(y => y.ParticipantId == participantId));

如何过滤 IList 子查询 EF Core 2.2

How to filter IList subquery EF Core 2.2

c#

asp.net-core-2.2

ef-core-2.2