Josep L Colom wrote: One way to reuse I taught was (if possible, but I don't know how) to convert those .h/.cpp clas(ses) to an ActiveX control. May be creating a new MFC ActiveX DLL project, and then, through interop to access this ActiveX (COM object). Although that's true in theory, since ActiveX type libraries can be imported in the .NET world, I believe you should engage this way only as last option. Reasons are : - the marshaler (type library importer) has a few bugs, and as a consequence it's likely you have issues when calling exposed interfaces. - you have to build the ActiveX first, which means you have to provide implementation for IOleClientSite and some other containers as well. Got my point ? You'll end drop dead before you get a simple MFC owner drawn derived control, working fine in the .NET world.