EF4 DbContext LINQ查询实体未标记为删除的位置

时间:2015-08-20 14:46:01

标签: c# linq entity-framework-4 dbcontext

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();

1 个答案:

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();