COM server interop

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Can't figure out how to create a managed wrapper for a com server.

I have COM interface which look like this in the .tlh file

IAddOn : IDispatch
{
virtual HRESULT __stdcall ObjectChanged (
/*[in]*/ int iObjectID,
/*[in,out]*/ VARIANT * varrChanged,
/*[out,retval]*/ int * piRet ) = 0;
};

Now I want to create a C++/CLI class that handles the ObjectChanged call
from a COM client.

In C# I do
[ProgId(..)]
[Guid(..]
public class MyAddon : IAddOn {
public int ObjectChanged(int id, ref object changed ) {
...
}
}

How do I create a managed class doing the same thing i C++/CLI without using
the interop assembly?