C# - Step 5.3 ComInterfaceType.InterfaceIsDual

ComInterfaceType.InterfaceIsDual - COM interface types supports both IDispatch and IUnknown mode.

When you use [InterfaceType(ComInterfaceType.InterfaceIsDual)], the following code will get generated on C++ client side with #import tlb file.

struct __declspec(uuid("12d1edac-20c0-4faa-a774-b6f4c300b47e"))

IMathCtrl : IDispatch

{

long AddNumbers (

long a,

long b );

virtual HRESULT __stdcall raw_AddNumbers (

/*[in]*/ long a,

/*[in]*/ long b,

/*[out,retval]*/ long * pRetVal ) = 0;

};

inline long IMathCtrl::AddNumbers ( long a, long b ) {

long _result = 0;

HRESULT _hr = raw_AddNumbers(a, b, &_result);

if (FAILED(_hr)) _com_issue_errorex(_hr, this, __uuidof(this));

return _result;

}

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