public __gc class Unknown
{
public:
  IntPtr GetInfo(System::Object *com)
  { ITypeInfo*    ti=NULL;
    IntPtr      ptr=IntPtr::Zero;
    IntPtr      ids=Marshal::GetIDispatchForObject(com);
    if(ids!=IntPtr::Zero)
    { ((IDispatch *)(ids.ToPointer()))->GetTypeInfo(0, 0, &ti);
      if(ti!=NULL) ptr=Convert::ToInt32((int)ti); 
    }
    return(ptr);
  }        
};

Unknown       tl=new Unknown();
IntPtr        un=tl.GetInfo(comObject); 
UCOMITypeInfo ss=Marshal.GetObjectForIUnknown(un) as UCOMITypeInfo;
UCOMITypeLib  tlb;
int           indx;
   // получить ITypeLib  
  ss.GetContainingTypeLib(out tlb, out indx);