在多个项目中使用相同的数据库

I have 2 projects in my solution: the first one is a ClassLibrary and the second is my Application. I'm using Entity Framework (Code First method) with Sql Server Compact in my second project. The question is how can I use the same database in bith my projects? I've tried to move all my Entities, DbContext and GenericRepository to my Library and I also tried to set connection string inside the code, but I keep receiving IInvalidOperationException:I have 2 projects in my solution: the first one