实体框架不包括联接中的子级

Question

我使用内部联接来返回实体框架(v6.2.0(的结果，并且以下代码不返回RouteWaypoints子级(即route.RouteWaypoints始终为null(。有趣的是，加载的是单个子项(Customer、OriginLocation等(，但不是多个子项：

public List<Route> GetAllForTripWithWaypoints(int tripId)
{
return (
from route in GetAllBaseWithWaypoints()
from tripTask in DbContext.TripTasks.Where(x =>
x.TripId == tripId && x.OriginLocationId == route.OriginLocationId)
select route
).ToList();
}
private IQueryable<Route> GetAllBaseWithWaypoints()
{
return DbContext.Routes
.Include(x => x.Customer)
.Include(x => x.OriginLocation)
.Include(x => x.DestinationLocation)
.Include(x => x.RouteWaypoints.Select(y => y.Location))
.OrderBy(x => x.OriginLocation.Name).ThenBy(x => x.DestinationLocation.Name)
.AsQueryable();
}

如果我只加载Route实体，这种方法确实有效，但当我执行联接时就不行了。作为参考，这确实成功地加载了子级：

public Route GetByIdWithWaypoints(int id, bool validateExists = true)
{
var route = GetAllBaseWithWaypoints().FirstOrDefault(x => x.Id == id);
if (validateExists && route == null)
throw new Exception("Route not found for id: " + id);
return route;
}

加入时如何保持它的工作状态？

Answer 1

我做了一个不完美的解决方法，对数据库进行了两次调用，效率稍低，但它解决了问题：

public List<Route> GetAllForTripWithWaypoints(int tripId)
{
var routeIds = (
from route in GetAllBase()
from tripTask in DbContext.TripTasks.Where(x =>
x.TripId == tripId && x.OriginLocationId == route.OriginLocationId)
select route.Id
).ToList();
return GetAllBaseWithWaypoints().Where(x => routeIds.Contains(x.Id)).ToList();
}