The type or namespace name 'Core' does not exist in the namespace

问题

I encounter this kind of error when I debug a project I already have EntityFramework.dll, System.Core.dll, System.Data.Entity but still Core is not referenced.

Can someone help me?

I'm having error in this Line

using System.Data.Entity.Core.Objects;

This is the error:

The type or namespace name 'Core' does not exist in the namespace 'System.Data.Entity' (are you missing an assembly reference?)

回答1:

Enrique, I had this problem crop up when I started opening a project on my desktop that I had normally been opening on my VM. Masoud's answer is not helpful... I don't think he read your original post.

What I did to clear this compile error up was to open NuGet package manager and install the update that was available for EntityFramework. I had version 6.1.1 installed in the project and I upgraded to 6.1.3. I should not have had the error to start with, but upgrading the version appeared to jiggle whatever it was loose because I started compiling fine after that.

回答2:

If you want use EF6, use namespace System.Data.Entity.Core instead, and try again.

Upgrading to EF6

来源：https://stackoverflow.com/questions/26092188/the-type-or-namespace-name-core-does-not-exist-in-the-namespace