The type initializer for threw an exception in entity framework model?

Question

I have 2 projects A and B
each project has its own database and connect to it using entity framework and each project is working well alone
My problem is that when I use the project B as a library inside the project A It gives me "The type initializer for (MYCLASS) threw an exception"
you should know that (MYCLASS): is an Entity inside the project B

Answer 1

Check if both projects are referring to the same version of entityframework in app.config . You might have upgraded your ef dlls in your project B but not in your project A. Since you have made reference of B in A, entityframework is using the config in A for both projects.

Answer 2

Install same version of EF to all project first and then check the following in the App.config file,

1. connectionStrings element is after the configSections element.
2. startup element is after the connectionStrings element.

<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <configSections>
         <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
   </configSections>
   <connectionStrings>
         <add name="SchedulingContext" connectionString="Data Source=XXX\SQL2008R2DEV;Initial Catalog=YYY;Persist Security Info=True;User ID=sa;Password=XXX"   providerName="System.Data.SqlClient"/>
   </connectionStrings>
   <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>       
 </configuration>

Answer 3

just remove all lines from ConfigSection

 <configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.4.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />