Mixing managed / unmanaged C ++?

I have a library written in standard C ++. I also have a .Net windows form application written in C # that uses an unmanaged library.

I understand that I can just use pinvoke, but my C ++ is completely OO, and I really would not want to bother with marshaling, etc.

Is there a way that I can simply create a new managed C ++ dll project, copy and paste my header and code files, and compile it and access all classes?

Or do I need to create some ref class in managed C ++ and connect it to my unmanaged class? I just want it to be as simple as possible.

Thank!