我似乎无法找到一种方法(想知道是否确实可行)在DBContext上执行LINQ查询,只提供未标记为删除的项目。
e.g。
// Mark one or more items in the DBContext for deletion.
(from di in DbContext.DeliveryItems where di.Id == myId select di).ToList().ForEach(di => this.Context.DeleteObject(di));
然后我可以执行一个忽略已删除对象的查询(当然不必触发SaveChanges())吗?
decimal? weight = (from s in this.Context.Stocks
where di.Id == myId
select s.GrossWeight).Sum();
即。我只想要未标记为删除的股票实体的权重总和。
编辑:无法获得ChangeTracker()参考资料,因此最终执行以下操作...
List<int> deletedDeliveryItems = this.Context.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Deleted)
.Where(x => x.EntityKey.EntitySetName == "DeliveryItems")
.Select(x => ((DeliveryItem)x.Entity).Id).ToList();
decimal? sumWeightOfDeletedDeliveryItems = (from s in DbContext.Stocks
where deletedDeliveryItems.Count > 0 &&
deletedDeliveryItems.Contains(s.Id)
select s.GrossWeight).Sum();
答案 0 :(得分:1)
var delete = (from di in DbContext.DeliveryItems where di.Id == myId select di).ToList();
delete.ForEach(di => this.Context.DeleteObject(di));
decimal? weight = (from s in this.Context.Stocks
where !delete.Select(di => di.Id).Contains(s.SomeId)
select s.GrossWeight).Sum();
如果由于某种原因需要从DbContext
获取已删除的项目。你可以这样做:
var deleted = context.ChangeTracker.Entries()
.Where(x => x.State == System.Data.EntityState.Deleted)
.Select(x=> x.Entity).ToList();