Referencing .NET Types from COM
From the point of view of client and server code, the differences between COM and the .NET Framework are largely invisible. Microsoft Visual Basic clients can view a .NET object in the object browser, which exposes the object methods and syntax, properties, and fields exactly as if it were any other COM object.
The process for importing a type library is slightly more complicated for C++ clients, although you use the same tools to export metadata to a COM type library. To reference .NET object members from an unmanaged C++ client, reference the TLB file (produced with Tlbexp.exe) with the #import directive. When referencing a type library from C++, you must either specify the raw_interfaces_only option or import the definitions in the base class library, Mscorlib.tlb.
To import a library without Mscorlib.tlb
To import a library with Mscorlib.tlb