实体框架创建空的迁移，但坚持认为我的模型是不同的 [英] Entity Framework creates empty migration but insists that my model is different
问题描述
今天是个悲伤的日子。第一件事，今天我看到了EF异常说的模型来头DomainContext语境自从创建数据库更改。的。这是接近午夜，我仍然看到此错误。这是我职业生涯结束 - （
Today is a sad day. First thing today I saw EF exception saying that "The model backing the 'DomainContext' context has changed since the database was created.". It is close to midnight and I still see this error. This is the end of my career -(
我敢肯定，一切都没有在模型中修改的，没有出现错误我试图创建一个新的迁移，它。出来了空：
I'm pretty sure nothing has changed in the model, yet the error appeared. I have tried creating a new migration, it came out empty:
public void Up()
{
}
public void Down()
{
}
应用这种迁移并没有任何好处 - 错误坚持我用共同建议设置初始化器为null。
Applying this migration did not do any good - the error persisted. I've used common suggestion to set the initialiser to be null:
Database.SetInitializer<DomainContext>(null);
和它使错误消失，当我访问数据库，但这个困扰我非常喜欢。 - 每当我尝试运行通过代码迁移，我再次看到类似的错误：
And it made the error go away when I access the database. But this bothers me very much - whenever I try to run migrations through code, I see similar error again:
var configuration = new Migrations.Configuration();
configuration.TargetDatabase = new DbConnectionInfo("correct connection string", "System.Data.SqlClient");
var migrator = new DbMigrator(configuration);
migrator.Update(); // <<-- exception is thrown here
异常抛出如下： System.Data.Entity.Migrations.Infrastructure.AutomaticMigrationsDisabledException：无法更新数据库，因为有挂起的变化，自动迁移禁用当前模型相匹配。无论是写一个基于代码的迁移挂起模式的变革或启用自动迁移。设置DbMigrationsConfiguration.AutomaticMigrationsEnabled为true启用自动迁移。的
我已经更新到6.1 EF（是在6.0.2之前），但这种再没。区别
I've updated to EF 6.1 (was on 6.0.2 before), but this made no difference.
这是困扰我，我可以通过的NuGet控制台运行迁移另一件事：
Another thing that bothers me that I can run migrations through Nuget Console:
Update-Database
运行良好，不给任何问题。但是，当我设置数据库初始化器自动运行迁移：
Runs fine and does not give any problems. But when I set DB initialiser to run migrations automatically:
var initializer = new MigrateDatabaseToLatestVersion<DomainContext, Migrations.Configuration>();
Database.SetInitializer(initializer);
var domainContext = new DomainContext();
domainContext.Database.Initialize(true); // <<-- this throws exception
的无法更新数据库匹配目前的模式，因为有挂起的更改，并自动迁移被禁用。无论是写一个基于代码的迁移挂起模式的变革或启用自动迁移。设置DbMigrationsConfiguration.AutomaticMigrationsEnabled为true启用自动迁移。的
真正的问题是为什么EF有机型不同的散列通的NuGet控制台，并通过迁移运行时DB-初始化器？我怎样才能找出什么不同（从DB-状态模型）？而如何解决这个问题，所以我没有用黑客（null分配到DB-initaliser）？
The real question is why does EF has different hashes for models when running through Nuget console and through Migrations DB-Initialiser? How can I find out what is different (model from db-state)? And how to fix this, so I don't have to use hacks (assign null to db-initaliser)?
推荐答案
的事业我的问题是应用到模型中的一个 [AllowHtml] 属性。麻烦开始我已经更新到MVC 5.1.1和的WebAPI到2.1之后发生的。
The cause to my problem was a [AllowHtml] attribute applied to one of the models. The trouble started to happen after I've updated MVC to 5.1.1 and WebApi to 2.1.
我已经移除EF-模式，属性和剥离并重新建立数据库，问题就消失了。
I've removed that attribute from EF-Model and stripped and re-build the database and the problem was gone.
我已经写了关于如何调试这类问题的博客帖子：的 http://tech.trailmax.info/2014/03/inside_of_ef_migrations/
I've written up a blog post on how to debug this kind of problems: http://tech.trailmax.info/2014/03/inside_of_ef_migrations/
另外，我觉得这个 [AllowHtml] 属性是一个错误，我将创建一个可重复的解决方案，将提交给EF-人的错误报告。
Also I think this [AllowHtml] attribute is a bug, I'll create a reproducible solution and will submit the bug report to EF-people.
更新：我其实永远无法重现错误。对类属性 [AllowHtml] 属性无关，用它做。一个神奇的毛刺即得。
Update: I actually could never reproduce the error. [AllowHtml] attribute on class properties had nothing to do with it. A magical glitch that was.
这篇关于实体框架创建空的迁移，但坚持认为我的模型是不同的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
