how to return failure HRESULTs from .NET to COM

[lakshmi]

Hi all
I posted a related question a couple days back. I did get
a few helpful replies. However, I've not yet figured out
the solution.

I've read that passing HRESULTs back from .NET to COM is
not a good practice. Exceptions should be thrown and sent
back to COM.

I'm rewriting a C++ program in C#. The C++ program used to
return an LPVARIANT type under success conditions and
HRESULTs under failure conditons. The C# dll is supposed
to return a System.object. When an error occurs, I throw
an exception back to the caller. The caller (a VB script
COM component) checks for FAILED(hr).

issues:
1.When an exception is thrown from .NET to the client,
FAILED(hr) is false. (I expected it to be true).

2.I tried to convert the exception into an HRESULT and
return it back to the caller (using
Marshal.GetHRForException() method.) In this case, I get a
VBScript runtime error because it is expecting a
System.object type to be returned from C#, instead an
Int32 HRESULT is returned.

Any help is appreciated.
thanks.