在Silverlight 4中访问麦克风时,防止网络摄像头灯亮起

我正在用Silverlight4编写一个小的音频录制器组件。它工作正常,但我注意到,当我录制音频时,网络摄像头上的灯亮起,表示摄像头处于活动状态。

要知道我没有对网络摄像头做任何阴险的事情,我的用户完全有权怀疑。是否可以告诉Silverlight我只对麦克风访问感兴趣,而不激活网络摄像头?

private CaptureSource _source = new CaptureSource();
private MemoryAudioSink _sink;  // Inherits from AudioSink. Doesn't do much more 
                                // than store PCM audio stream in memory

private void Record_Click(object sender, RoutedEventArgs e)
{
    if (( CaptureDeviceConfiguration.AllowedDeviceAccess || 
          CaptureDeviceConfiguration.RequestDeviceAccess() ) && 
        _source.State == CaptureState.Stopped)
    {
        _sink = new MemoryAudioSink();
        _sink.CaptureSource = _source;
        _source.Start();
    }
}