【The instance of entity type 'Model' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked.】的更多相关文章

The instance of entity type 'xxxx' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked.

一.问题描述 问题:The instance of entity type 'xxxx' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is atta…

The instance of entity type 'Menu' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked.

这里记录一个在使用.net core中ef core执行数据库操作时遇到的问题: 我在代码中使用DbContext下的Update方法准备将更改后的数据像这样步到数据库: _context.Menus.Update(menu); 这是很常见的用法,但没想到一直报如下错误: The instance of entity type 'Menu' cannot be tracked because another instance with the same key value for {'Id'}…

EF 更新实体 The instance of entity type 'BabyEvent' cannot be tracked because another instance

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The instance of entity type 'manager' cannot be tracked because another instance with the same key value for {'id'} is already being tracked. When attaching existing entities, ensure that only one ent

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The entity type XXX is not part of the model for the current context.

今天遇到了一个奇葩问题,虽然解决了,但还是一脸懵,先附赠一下别人的解决方案:https://www.cnblogs.com/zwjaaron/archive/2012/06/08/2541430.html(我是参考这篇文章解决的,但是问题不一样). 先描述一下我的问题吧: 我们的项目的发布流程是,本地开发完成,提交测试环境,测试完成,提交业务测试环境,最终上线.前情提要:我们的新版本开发完成了,但是测试时间充裕,我们就进行了下一个迭代的开发,作为一个严肃的开发者,自己已经经过了测试环境的自测.然…

Entity Framework的核心 – EDM(Entity Data Model) 一

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Create Entity Data Model

http://www.entityframeworktutorial.net/EntityFramework5/create-dbcontext-in-entity-framework5.aspx 官网的教程https://msdn.microsoft.com/en-us/data/jj206878 Here, we are going to create an Entity Data Model (EDM) for SchoolDB database and understand the ba…

[转] EF cannot be tracked because another instance of this type with the same key is already being tracked

本文转自:http://stackoverflow.com/questions/6033638/an-object-with-the-same-key-already-exists-in-the-objectstatemanager-the-object cannot be tracked because another instance of this type with the same key is already being tracked If you load the entity…

Entity Framework Tutorial Basics（5）：Create Entity Data Model

Create Entity Data Model: Here, we are going to create an Entity Data Model (EDM) for SchoolDB database and understand the basic building blocks. Entity Data Model is a model that describes entities and the relationships between them. Let's create fi…