I recently updated entity framework version 5, afterwards whenever tried to add a controller with the entity framework template I got this error message. This issue was resolved by removing <providers> from the <entityFramework > section.
Problem:
<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>
Solution:
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory,EntityFramework">
<parameters>
<parameter value="v11.0" />
</parameters>
</defaultConnectionFactory>
</entityFramework>
Again, if you are facing any problem I recommended following steps:
Step 1: You to delete the files from bin folder and building the project. Check bin folder if your project dll is excluded, then include it and rebuild the project.
Step 2: Close the project and reopen it.