how can i capure just one channel buffer use WSAPI (WinRT)?

Question

WAVEFORMATEX* pwfx = new WAVEFORMATEX();
pwfx->wFormatTag = WAVE_FORMAT_PCM;
pwfx->nSamplesPerSec = 44100;
pwfx->wBitsPerSample = 16;
pwfx->nChannels = 1;
pwfx->nBlockAlign = pwfx->nChannels * pwfx->wBitsPerSample / 8;
pwfx->nAvgBytesPerSec = pwfx->nBlockAlign * pwfx->nSamplesPerSec;
pwfx->cbSize = 0;
        hr = m_AudioClient->Initialize( AUDCLNT_SHAREMODE_SHARED,
                                        AUDCLNT_STREAMFLAGS_EVENTCALLBACK,
                                        200000,
                                        0,
                                        pwfx,
                                        nullptr );

the code can't work if my audio device only have 1channel, m_AudioClient->Initialize get error 0x88890008

it gets ok if my audio device has 2 channels.

now i only want to get 1 channel buffer event the audio device has 2 channels, how can i do this?

"waveInOpen" can do this use the same parameters, but the API can't use in Metro app