如何在实体框架中有效地获取实体及其子对象的 IList？

发布于 2024-09-28 05:00:40 字数 335 浏览 2 评论 0原文

也就是说，我想这样做：

var lists = (from list in this.DB.Lists
             select new
             {
                 List = list,
                 Items = list.ListItems.ToList(),
             }).ToList();

但是，显然，实体框架不支持 select 子句中的 ToList 扩展方法。

我应该怎么办？我尝试过的任何其他方法最终都会在迭代时向数据库发送大量查询。

原文

That is, I want to do this:

var lists = (from list in this.DB.Lists
             select new
             {
                 List = list,
                 Items = list.ListItems.ToList(),
             }).ToList();

But, obviously, the Entity Framework doesn't support the ToList extension method in the select clause.

What should I do? Any other method I've tried ends up sending a ton of queries to the database when iterating.

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压抑⊿情绪 2024-10-05 05:00:40

您是否尝试过 Include etension 方法？

var lists = (from list in this.DB.Lists.Include("ListItems")
             select list).ToList(); 

foreach(var item in lists)
{
   // there shouldn't be any DB calls here.
   var items = list.ListItems.ToList();
}

Have you tried the Include etension method?

var lists = (from list in this.DB.Lists.Include("ListItems")
             select list).ToList(); 

foreach(var item in lists)
{
   // there shouldn't be any DB calls here.
   var items = list.ListItems.ToList();
}

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清晰传感 2024-10-05 05:00:40

您无法对转换为 SQL 的查询部分调用 ToList，但您可以使用 AsEnumerable 在本地执行此操作：

var lists = (from list in this.DB.Lists.AsEnumerable()
             select new
             {
                 List = list,
                 Items = list.ListItemsItems.ToList()
             }).ToList();

You can't call ToList on the part of the query that is translated to SQL, but you can do it locally, using AsEnumerable:

var lists = (from list in this.DB.Lists.AsEnumerable()
             select new
             {
                 List = list,
                 Items = list.ListItemsItems.ToList()
             }).ToList();

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