C# 实体框架:如何在模型对象上组合 .Find 和 .Include? [英] C# Entity-Framework: How can I combine a .Find and .Include on a Model Object?

问题描述

我正在做 mvcmusicstore 练习教程.我在为相册管理器创建脚手架时注意到了一些东西(添加删除编辑).

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

我想优雅地编写代码，所以我正在寻找一种简洁的方式来编写代码.

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

仅供参考，我正在使商店更通用:

FYI i'm making the store more generic:

相册 = 项目

流派 = 类别

艺术家 = 品牌

以下是检索索引的方式(由 MVC 生成):

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

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

这里是如何检索要删除的项目:

Here is how the item for delete is retrieved:

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

第一个带回所有项目并填充项目模型中的类别和品牌模型.第二个，不填充类别和品牌.

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.

我如何编写第二个来进行查找并填充里面的内容(最好在 1 行中)...理论上 - 类似于:

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);

推荐答案

您可以先使用 Include()，然后从结果查询中检索单个对象:

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

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

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