C# string[] to VARIANT* for COM

[vijusharma]

Hello,
I have the following COM definition, which supposedly takes in a vector of strings.
************** IDL *************************
[id(1), helpstring("method myMethod")]
HRESULT myMethod( [in] VARIANT* bFlags, [out,retval] VARIANT* result);
************** IDL *************************

I Have an example using C++ where the method is called

***************** C++ *******************

void
initComVariantArray( const std::vector<std::string>& inputFlags,
                     CComVariant& rOutputFlags )
                     throw ( _com_error )
{
    rOutputFlags.ChangeType( VT_VARIANT );
 
    CComSafeArray<VARIANT> inputArray( (ULONG) 0 );
    for ( unsigned int i = 0; i < inputFlags.size(); ++i )
    {
        CComVariant comPacsKey;
        CComBSTR tmpString( inputFlags[i].c_str() );
 
        // The operator= will set automatically the type to VT_BSTR
        comPacsKey = tmpString;
 
        HRESULT hr = inputArray.Add( comPacsKey );
        if ( FAILED( hr ) )
        {
            throw _com_error( hr );
        }
    }
 
    // The operator= will add automatically the type VT_ARRAY to the vt
    rOutputFlags = inputArray;
}
 
 Main():
{
CComVariant vFlags;
vector<string> vecFlags(); vecFlags.push_back( "flag1" );
initComVariantArray( vecFlags, vFlags );
CComVariant vResult = pInteface->myMethod( (&vFlags );
}
 

***************** C++ *******************

This works great with C++, but i can't get the interface to work in C#. when i import the interface into C#, i get the following definition:

*************** C# ************************

myMethod( ref object );
 
and calling the method as:
string [] flags = { "flag1" };
object objFlag = ( object ) flags;
myMethod( ref objFlag );

Does not work. I get the exception:
System.Runtime.InteropServices.SEHException: External component has thrown an exception.
*************** C# ************************

If you guys know what im doing wrong here, it would be a lot of help.

Thanks in advance.

[Plater]

It says external component threw an exception. What exception did the external(com) component throw?