Your project references the latest version of Entity Framework; however, an Entity Framework database provider compatible with this version could not be found for your data connection. If you have already installed a compatible provider, ensure you have rebuilt your project before performing this action. Otherwise, exit this wizard, install a compatible provider, and rebuild your project before performing this action.
Update: The project multiple layers based on onion architecture. I have realised that I am able to add new model to other solutions / layers. However I'm not able to add this one which I keep most of my models.
My system properties:
What I have tried
<provider invariantName="Oracle.ManagedDataAccess.Client" type="Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices, Oracle.ManagedDataAccess.EntityFramework, Version=220.127.116.11, Culture=neutral, PublicKeyToken=89b483f429c47342" />
<defaultConnectionFactory type="Oracle.ManagedDataAccess.EntityFramework.OracleConnectionFactory, Oracle.ManagedDataAccess.EntityFramework"> </defaultConnectionFactory>
I have uninstall both ODT and ODAC and installed and installed previous release of them.
I ve downgraded Entity Framework from 6.1.3 to 6.0.
I have change project build option from "Any CPU" to "32 bit" and tried installed all the components accordingly in 32 bit. Didn't work.
I have checked or compared web config and app config files which contains any configuration about oracle and entity framework, but couldn't see anything wrong.
After trying all these, I recreated the solution which I used to keep model classes and now I am able to add model. Problem solved.