如何实现IDbContextFactory用于实体框架数据迁移 [英] How to implement IDbContextFactory for use with Entity Framework data migrations

问题描述

我正在尝试使用Entity Framework数据迁移，如这篇文章。

I am trying to use Entity Framework data migrations, as described in this post.

但是，当我尝试执行启用迁移步骤，我在软件包管理器控制台中收到以下错误：

However, when I try to execute the Enable-Migrations step, I receive the following error in Package Manager Console:

The target context 'MyDataContext' is not constructible. Add a default constructor or provide an implementation of IDbContextFactory

所以，我创建了一个实现<$包含我的 DbContext 类的项目中的c $ c> IDbContextFactory ，但数据迁移似乎不能识别它。

So, I created a factory class that implements IDbContextFactory in the project that contains my DbContext class, but data migrations doesn't appear to recognize it.

有什么我应该明确地指出数据迁移使用这个工厂类吗？

Is there something that I should explicitly do to instruct data migrations to use this factory class?

推荐答案

我也碰到这个问题，因为我写了我的上下文来连接字符串名称（然后使用ninject来提供它）。

I also hit this problem as i wrote my context to take a connection string name (and then used ninject to provide it).

你已经走过的过程通过似乎是正确的，如果有任何帮助，这里是我的类实现的代码片段：

The process you've gone through seems correct, here is a snippet of my class implementation if it's of any help:

public class MigrationsContextFactory : IDbContextFactory<MyContext>
{
    public MyContext Create()
    {
        return new MyDBContext("connectionStringName");
    }
}

这应该是你需要的。

这篇关于如何实现IDbContextFactory用于实体框架数据迁移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！