Bug: How to fix Exception Could not load file or assembly 'EntityFramework, Version=4.0.0.0[…]' or o

原文： http://www.cnetion.com/how-to-fix-exception-could-not-load-file-or-assembly-entityframework-version-4-qq-AUvBha09ivICeoL1jpEq.php

问题：

I installed EF6 and then realized MySQL has yet to provide support for it on their Connector/Net. So Naturally I rolled back and now I'm getting the error cited in the title.

My app.config looks like this

<?xml version="1.0" encoding="utf-8"?><configuration>  <configSections>    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->  </configSections>  <entityFramework>    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">      <parameters>        <parameter value="v11.0" />      </parameters>    </defaultConnectionFactory>  </entityFramework></configuration>

and my references look like:

Name: EntityFramework.dll
Created By: Microsoft Corporation
Verison: 5.0.20627.0

Additionally I have referenced the following assemblies:

Name: System.Data
Version: 4.0.0.0
File Version: 4.030319.17929

Name: System.Data.Entity
Version: 4.0.0.0
File Version: 4.030319.17929

The Exact text of the Exception I get is:

An error occurred creating the configuration section handler for entityFramework: Could not load file or assembly 'EntityFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

How can I fix this??

回答：

Your configuration refference version and installed versions are mismatch.You should change the following line of code ,because of you refference entityframework version 5.0.0.0 dll.So just try with replacing following line of code.

<section name="entityFramework"           type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"           requirePermission="false" />