Re: How to instantiate an [appobject] coclass

From:
"Drew" <dam@dam.com>
Newsgroups:
microsoft.public.vc.atl
Date:
Fri, 9 Oct 2009 13:20:02 -0500
Message-ID:
<Of9Zl1QSKHA.4568@TK2MSFTNGP06.phx.gbl>
"Barzo" <dbarzo@gmail.com> wrote in message
news:aa9a107b-b9d3-431d-8f4d-975276568f1c@k33g2000yqa.googlegroups.com...

Hi,

in my DLL I have a coclass defined with [appobject] attribute:

-------------------------------------------------------------------------------
[
object,
uuid(AB566C82-AF54-11DE-B5BE-00A0D15E9B20),
dual,
nonextensible,
helpstring("IAudioLib Interface"),
hidden,
pointer_default(unique)
]
interface IAudioLib : IDispatch
{
 [id(1), helpstring("Retrieve the library version.")]
 HRESULT GetLibVersion([out, retval] BSTR* pVal);
 [id(2), helpstring("Retrieve the error description.")]
 HRESULT RetValToStr([in] E_AUDIOLIB_RET_VAL rv, [out, retval] BSTR*
pVal);
 [id(3), helpstring("Retrieve the number of devices for a specific
API.")]
 HRESULT GetDeviceCount([in] E_AUDIO_API audio_api, [out, retval]
short* pVal);
 [id(4), helpstring("Retrieve the informations of a single device.")]
 HRESULT GetDeviceInfo([in] long device,
                       [in] E_AUDIO_API audio_api,
                       [in, out] T_DeviceInfo* retDevInfo,
                       [out, retval] E_AUDIOLIB_RET_VAL* pVal);
 [id(5), helpstring("Retreive an array containing informations for
all devices.")]
 HRESULT GetDevicesInfo([in] E_AUDIO_API audio_api, [out, retval]
SAFEARRAY(T_DeviceInfo)* pVal);
};
....
....
[
 uuid(AB566C81-AF54-11DE-B5BE-00A0D15E9B20),
 appobject,
 helpstring("AudioLib Class")
]
coclass AudioLib
{
 [default] interface IAudioLib;
};
-------------------------------------------------------------------------------

I have implemented all the IAudioLib methods in AudioLib.cpp but, in
VB6, when I call a method:

MgsBox AxAudioLib4.GetLibVersion


--------------------
What is AxAudioLib4? I'll have to assume it's something like:

Dim AxAudioLib4 as NameOfCOMLibrary.AudioLib

and somewhere before you call AxAudioLib4.GetLibVersion you've done this:

Set AxAudioLib4 = new NameOfCOMLibrary.AudioLib

If either of the above is incorrect then that's your problem.

Drew

I get the error:
Runtime Error 429, "ActiveX component can't create object"

This kind of classes have to be implemented (or created) in a special
way?

Thanks,
Daniele.

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