识别实体框架的版本

Question

One of our development machines is giving an error saying that DbContext does not implement IDisposable . According to a similar SO post , this is because we are not referencing EF 5. The problem assembly has a *.edmx file built with older EF 4 constructs ( ObjectContext ). This same assembly also has a newly added *.edmx file with the newer constructs ( DbContext ).

A different project on a different machine also uses DbContext and works fine. Said project shows the following information for EntityFramework.dll :

version:  4.4.0.0
Runtime Version:  v4.0.30319

I checked the bad build machine and it also has this same version of EntityFramework.dll .

Microsoft has had confusing conflicts between development and marketing version naming conventions. So does EF 5 mean the dll version should say 5.0?

In other words, am I running v4.0 on the good build machine? If so why is the build successful?

Answer 1

The Entity Framework v5.0 dll is dependent on the .NET CLR you are targeting. If your project is set to use the .NET 4.0 framework, the runtime version of the EntityFramework.dll will be 4.4.0.0.

If you are using Entity Framework with a CLR target of .NET 4.5, the version of the EntityFramework.dll will be 5.0.

When you add EntityFramework via nuget, it will look at your project's CLR target runtime and add the appropriate EntityFramework.dll reference. If you later change your target, you should uninstall and reinstall the EntityFramework reference via nuget to make sure that the correct version of the runtime is referenced by your project.

Reference post by Julie Lerman about the topic.