在Entity Framework中从.net 4.5.2更改为4.0的版本问题

Question

I have an .edmx file which includes a lot of tables. The file is inside a project created with .NET 4.5.2. But my other projects are using .NET version 4.0 and i can not refer this project. I have to change my used .NET version to 4.0. But it gives me an error below while rebuild process. I can not solve this.

The primary reference "EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=MSIL" could not be resolved because it was built against the ".NETFramework,Version=v4.5" framework. This is a higher version than the currently targeted framework ".NETFramework,Version=v4.0".

Answer 1

You need to reinstall EF6 using nuget as explained here: https://docs.microsoft.com/en-us/nuget/consume-packages/reinstalling-and-updating-packages

Go to Tools > NuGet Package Manager > Package Manager Console Then type Update-Package -Id EntityFramework -Version 6.0.0 –reinstall

You might need to edit your packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
    <package id="EntityFramework" version="6.0.0" />

    <!-- ... -->
</packages>

Answer 2

EF has both a net40 folder and a net45 folder. You are most likely referencing the dll in net45. If you uninstalled the package and reinstalled as CodeCaster suggested, then you may have a stuck reference in your csproj file. You can try this:

1. Right click your web project and choose "Unload Project". Now you can right click and edit it.
2. Look for the reference path and if it says \\net45 change it to \\net40
3. Right click and reload project.

<Reference Include="EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=MSIL">

<HintPath>..\\packages\\EntityFramework.6.1.3\\lib\\net45\\EntityFramework.dll</HintPath> <Private>True</Private>

</Reference>