[c#] An unhandled exception of type 'System.TypeInitializationException' occurred in EntityFramework.dll

I was trying to learn Entity Framework and SQLite using this tutorial. However, I get an error.

The error thrown is:

An unhandled exception of type 'System.TypeInitializationException' occurred in EntityFramework.dll

Additional information: The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception.

Here is the full error trace:

System.TypeInitializationException: The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception. ---> System.Configuration.Configuration
ErrorsException: Configuration system failed to initialize ---> System.Configuration.ConfigurationErrorsException: Only one <configSections> element allowed per config file and if present must be the first child of the root <configuration>
element. (C:\Users\Ankur\Documents\Visual Studio 2012\Projects\ConsoleApplication1\ConsoleApplication1\bin\Debug\ConsoleApplication1.vshost.exe.config line 11)
   at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal)
   at System.Configuration.BaseConfigurationRecord.ThrowIfParseErrors(ConfigurationSchemaErrors schemaErrors)
   at System.Configuration.BaseConfigurationRecord.ThrowIfInitErrors()
   at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
   --- End of inner exception stack trace ---
   at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
   at System.Configuration.ClientConfigurationSystem.PrepareClientConfigSystem(String sectionName)
   at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)
   at System.Configuration.ConfigurationManager.get_ConnectionStrings()
   at System.Data.Entity.Internal.AppConfig..ctor()
   at System.Data.Entity.Internal.AppConfig..cctor()
   --- End of inner exception stack trace ---
   at System.Data.Entity.Internal.AppConfig.get_DefaultInstance()
   at System.Data.Entity.Internal.LazyInternalConnection..ctor(String nameOrConnectionString)
   at System.Data.Entity.DbContext..ctor()
   at ConsoleApplication1.ChinookContext..ctor()
   at ConsoleApplication1.Program.Main(String[] args) in c:\Users\Ankur\Documents\Visual Studio 2012\Projects\ConsoleApplication1\ConsoleApplication1\Program.cs
:line 16

Here is the C# code:

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            using (var context = new ChinookContext()) //error comes on this line
            {
            }
        }
    }

    class ChinookContext : DbContext
    {
    }
}

Here is file App.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.data>
    <DbProviderFactories>
      <add name="SQLite Data Provider" invariant="System.Data.SQLite" description="Data Provider for SQLite" type="System.Data.SQLite.SQLiteFactory, System.Data.SQLite" />
    </DbProviderFactories>
  </system.data>
  <connectionStrings>
    <add name="ChinookContext" connectionString="Data Source=|DataDirectory|Chinook_Sqlite_AutoIncrementPKs.sqlite" providerName="System.Data.SQLite" />
  </connectionStrings>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
  </configSections>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
  </entityFramework>
</configuration>

Here is file packages.config:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="5.0.0" targetFramework="net45" />
  <package id="System.Data.SQLite.x86" version="1.0.86.0" targetFramework="net45" />
</packages>

Check which version of Entity Framework reference you have in your References and make sure that it matches with your configSections node in Web.config file. In my case it was pointing to version 5.0.0.0 in my configSections and my reference was 6.0.0.0. I just changed it and it worked...

<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false"/>

Just go to Web.Config from Main folder, not the one in Views Folder:

configSections

section name="entityFramework" type="System.Data. .....,Version=" <strong>5</strong>.0.0.0"..

<..>

ADJUST THE VERSION OF EntityFramework you have installed, ex. like Version 6.0.0.0"

Check that right version is referenced in your project. E.g. the dll it is complaining about, could be from an older version and that's why there could be a version mismatch.

In static class, if you are getting information from xml or reg, class tries to initialize all properties. therefore, you should control if the config variable is there otherwise properties will not initialize so the class.

Check xml referance variable is there, Check reg referance variable is is there, Make sure you handle if they are not there.

I had this issue when i refereed a library project from a console application, and the library project was using a nuget package which is not refereed in the console application. Referring the same package in the console application helped to resolve this issue.

Seeing the Inner exception can help.