.NET Standard 2.0/EntityFrameworkCore/DB2/IBM.EntityFrameworkCore 问题 [英] .NET Standard 2.0 / EntityFrameworkCore / DB2 / IBM.EntityFrameworkCore issue

问题描述

这里有人有使用 IBM.EntityFrameworkCore 包的经验吗?我在 VS2017 中创建了一个 .NET Standard 2.0 库项目，添加了提到的包，并尝试按照 this 和 this 教程来自 IBM 网站，没有运气.我编译了项目，但在运行时我收到一个带有以下消息的 System.TypeLoadException:

Does anyone here has experience with IBM.EntityFrameworkCore package? I've created a .NET Standard 2.0 library project in VS2017, added mentioned package, and tried to make it work by following this and this tutorial from IBM website, with no luck. I get the project compiled, but at the runtime I'm getting a System.TypeLoadException with the following message:

Method 'ApplyServices' in type 'IBM.EntityFrameworkCore.Infrastructure.Internal.Db2OptionsExtension' from assembly 'IBM.EntityFrameworkCore, Version=1.1.1.101, Culture=neutral, PublicKeyToken=7c307b91aa13d208' does not have an implementation.

任何帮助将不胜感激！

谢谢！

更新:只要我尝试使用上下文，就会发生异常.这意味着 after 上下文创建成功，但 before DbContext.OnConfiguring 调用发生.

Update: The exception happens as soon as I try to use the context. It means after the context is successfully created, but before DbContext.OnConfiguring call happens.

推荐答案

我已经解决了.事实证明，如果实际实体类型(即 MyType)未在与上下文相同的程序集(项目)中定义，则会发生此异常.在我的解决方案中，我在一个项目中定义了实体类型，在另一个项目中定义了 DbContext，当然，它引用了第一个.

I've solved it. It turned out that this exception happens if actual entity types (i.e. MyType) aren't defined in the same assembly (project) as the context. In my solution I had entity types defined in one project, and DbContextdefined in a different project, that references the first one, of course.

我有这样设计的原因是有两个不同的包(取决于实际的操作系统):IBM.EntityFrameworkCore 和 IBM.EntityFrameworkCore-lnx.所以我创建了两个不同的项目，每个项目都引用了这些包之一.尽管如此，我还是想一次性定义所有实体类型……但显然它不能那样工作.

The reason for me to have such design was in the fact that there are two different packages (depending on the actual OS): IBM.EntityFrameworkCore and IBM.EntityFrameworkCore-lnx. So I've created two different projects, each referencing one of these packages. Still, I wanted to have all the entity types defined once... But obviously it cannot work like that.

更新:遗憾的是，事实证明这并不是唯一的问题.我遇到了另一个，在此处进行了描述.为 DB2 .NET 团队点赞！与...一起工作总是令人沮丧...

Update: Sadly, it turned out that this isn't the only issue. I've ran into another one, described here. Thumbs down for DB2 .NET team! It's always frustrating to work with...

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