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IAudioEffectsChangedNotificationClient 介面 (audioclient.h)

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回呼介面可讓應用程式在相關聯音訊數據流的音訊效果清單變更或啟用效果所需的資源變更時接收通知，也就是當相關聯AUDIO_EFFECT變更的 canSetState 欄位值變更時。

繼承

IAudioEffectsChangedNotificationClient 介面繼承自 IUnknown 介面。

方法

IAudioEffectsChangedNotificationClient 介面具有這些方法。

 
IAudioEffectsChangedNotificationClient：：OnAudioEffectsChanged

當音訊效果清單變更或啟用效果變更所需的資源時，由系統呼叫。

備註

呼叫 IAudioEffectsManager：：RegisterAudioEffectsChangedNotificationCallback 來註冊回呼介面。

範例

下列程式代碼範例示範的類別會實作 IAudioEffectsChangedNotificationClient ，以在音訊效果清單變更或啟用效果變更所需的資源時接收通知。 在 OnAudioStreamEffectsChanged 回呼中，此範例會呼叫 GetAudioEffects 以取得目前的效果清單。

class AudioEffectsChangedHandler :
    public winrt::implements<AudioEffectsChangedHandler, IAudioEffectsChangedNotificationClient>
{

    public:
    AudioEffectsChangedHandler(_In_ IAudioClient *client) : m_client(client){}
    STDMETHOD(OnAudioEffectsChanged)()
    {
        OnAudioStreamEffectsChanged(m_client.get());
        return S_OK;
    }
    private:
    wil::com_ptr_nothrow<IAudioClient> m_client;

};

wil::com_ptr_nothrow<IAudioEffectsChangedNotificationClient> g_effectsChangedHandler;

HRESULT RegisterAudioStreamEffectsChangedEvent(_In_ IAudioClient *client)
{
    if (!g_effectsChangedHandler)
    {
        wil::com_ptr_nothrow<IAudioEffectsManager> audioEffectsManager;
        RETURN_IF_FAILED(client->GetService(IID_PPV_ARGS(&audioEffectsManager)));

        // Register for the audio effects changed notification
        g_effectsChangedHandler = winrt::make<AudioEffectsChangedHandler>(client).get();
        RETURN_IF_NULL_ALLOC(g_effectsChangedHandler);

        return audioEffectsManager->RegisterAudioEffectsChangedNotificationCallback(
            g_effectsChangedHandler.get());
    }
    return S_OK;
}

HRESULT UnregisterAudioStreamEffectsChangedEvent(_In_ IAudioClient *client)
{
    if (g_effectsChangedHandler != nullptr)
    {
        wil::com_ptr_nothrow<IAudioEffectsManager> audioEffectsManager;
        RETURN_IF_FAILED(client->GetService(IID_PPV_ARGS(&audioEffectsManager)));

        // Unregister from the audio effects changed notification 
        return audioEffectsManager->UnregisterAudioEffectsChangedNotificationCallback(
            g_effectsChangedHandler.get());
        }

        return S_OK;
}

HRESULT OnAudioStreamEffectsChanged(_In_ IAudioClient *client)
{
    // Re-query the list of effects since there was some change
    wil::com_ptr_nothrow<IAudioEffectsManager> audioEffectsManager;
    RETURN_IF_FAILED(client->GetService(IID_PPV_ARGS(&audioEffectsManager)));
    wil::unique_cotaskmem_array_ptr<AUDIO_EFFECT> effects;
    UINT32 numEffects;
    RETURN_IF_FAILED(audioEffectsManager->GetAudioEffects(&effects, &numEffects));

    for (UINT32 i = 0; i < numEffects; i++)
    {

        // Here the app can check which effects are still enabled, and check if there are new
        // effects that now can be enabled.
        // As an example, the following code enables any effect that can be enabled, if it is not
        // already enabled.
        if (effects[i].canSetState && effects[i].state == AUDIO_EFFECT_STATE_OFF)
        {
            HRESULT hr = audioEffectsManager->SetAudioEffectState(effects[i].id, AUDIO_EFFECT_STATE_ON));
            if (hr == AUDCLNT_E_EFFECT_NOT_AVAILABLE || hr == AUDCLNT_E_EFFECT_STATE_READ_ONLY)
            {
                hr = S_OK;
            }
            RETURN_IF_FAILED(hr);

        }
    }

    return S_OK;
}

規格需求

需求 值
最低支援的用戶端 Windows 組建 22000
標頭 audioclient.h

另請參閱

AUDIO_EFFECT

IAudioEffectsManager：：RegisterAudioEffectsChangedNotificationCallback