C＃实体框架：如何可以结合.Find和.INCLUDE一个模型对象？ [英] C# Entity-Framework: How can I combine a .Find and .Include on a Model Object?

问题描述

我做的mvcmusicstore实践教程。创建相册管理器支架（添加删除编辑）时，我注意到的东西。

我要优雅地写code，所以我在寻找清洁的方式来写这个。

FYI我正在做实体店更通用的：

专辑=项目

流派=分类

艺术家=品牌

下面是该指数如何检索（由MVC生成）：

  VAR项目= db.Items.Include（I =＆GT; i.Category）.INCLUDE（I =＆GT; i.Brand）;
 

下面是如何对删除的项进行检索：

 项项= db.Items.Find（ID）;
 

第一个带回的所有项目，并填充项目模型内部的品类和品牌车型。第二个，不填充品类和品牌。

我怎么能写第二个做查找和填充里面什么（$ P在1号线pferably $）...理论上 - 是这样的：

 项项= db.Items.Find（ID）.INCLUDE（I =＆GT; i.Category）.INCLUDE（I =＆GT; i.Brand）;
 

解决方案

您需要使用包括（），然后再检索结果查询单个对象：

 逐项= db.Items
              .INCLUDE（I =＆GT; i.Category）
              .INCLUDE（I =＆GT; i.Brand）
              .SingleOrDefault（X =＆GT; x.ItemId == ID）;
 

I'm doing the mvcmusicstore practice tutorial. I noticed something when creating the scaffold for the album manager (add delete edit).

I want to write code elegantly, so i'm looking for the clean way to write this.

FYI i'm making the store more generic:

Albums = Items

Genres = Categories

Artist = Brand

Here is how the index is retrieved (generated by MVC):

var items = db.Items.Include(i => i.Category).Include(i => i.Brand);

Here is how the item for delete is retrieved:

Item item = db.Items.Find(id);

The first one brings back all the items and populates the category and brand models inside the item model. The second one, doesn't populate the category and brand.

How can i write the second one to do the find AND populate whats inside (preferably in 1 line)... theoretically - something like:

Item item = db.Items.Find(id).Include(i => i.Category).Include(i => i.Brand);

解决方案

You need to use Include() first, then retrieve a single object from the resulting query:

Item item = db.Items
              .Include(i => i.Category)
              .Include(i => i.Brand)
              .SingleOrDefault(x => x.ItemId == id);

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