Entity Framework ADO.NET Sql.Data.Client provider not found

Question

I have a similar problem as the one presented in the question No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient', the error has the following message:

"The ADO.NET provider with invariant name 'System.Data.SqlClient' is either not registered in the machine or application config file, or could not be loaded. See the inner exception for details."

As the answers to the related question suggest, I have reinstalled Entity Framework (EF6) via the Package Manager Console, but the error persists. I also checked that EntityFramework.SqlServer.dll is referenced in my project. Here is the connection string as stored in App.config:

<add name="DesignModel"    ConnectionString="metadata=res://*/DesignModel.csdl|res://*/DesignModel.ssdl|res://*/DesignModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=C071E;initial catalog=CTD2;integrated security=True;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />     

I have another project where I used EntityFramework to create the exact same entities and context, and it works fine, which makes this all more puzzling.

The error is shown when trying to execute this lines:

DesignModel designContext = new DesignModel();
designContext.MoPerfIDs.Load();

where DesignModel is the name of the class that inherits DbContext.

Here's the full App.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
       <section name="ppe.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
    </sectionGroup>
    <!-- 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=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>

  <connectionStrings>
    <add name="DesignModel" connectionString="metadata=res://*/DesignModel.csdl|res://*/DesignModel.ssdl|res://*/Design    Model.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=MONNMC071E;initial catalog=CTD2;integrated security=True;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

<entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
        <parameters>
            <parameter value="System.Data.SqlClient" />
        </parameters>
    </defaultConnectionFactory>
    <providers>
        <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
</entityFramework>
</configuration>

Any help will be appreciated. Thanks in advance.

Answer 1

You need to register the Entity Framework provider for the System.Data.SqlClient SQL connection type. you should have in app.config:

<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=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>

Answer 2

Still not sure what was causing the problem, but ended up creating a new solution and copying everything from my project. Now works fine. Really weird, indeed.