怎样才能用c#列出播放声音的音频设备？

用 cscore 你可以做到这一点

using (var enumerator = new MMDeviceEnumerator())
using (var collection = enumerator.EnumAudioEndpoints(DataFlow.All, DeviceState.All))
// ^^^ take a look on parameters here, you can filter devices with it
    foreach (var device in collection)
       //your device using here
       //don't forget to dispose device, because it is MMDevice which inherited from IDiposable
那么，让我们设想一下，你想检查当前的游戏水平
 using (var meter = AudioMeterInformation.FromDevice(device))
     if(meter.PeakValue > 0)
         //your code here
如果你需要通过输出过程来过滤输出设备，请看一下 AudioSession
using (var sessionManager = GetDefaultAudioSessionManager2(DataFlow.Render))
using (var sessionEnumerator = sessionManager.GetSessionEnumerator())
    foreach (var session in sessionEnumerator)
            //each session will be assigned to any process
            //implement your logic to select preferred
        using (var meterInformation = session.QueryInterface<AudioMeterInformation>())
            var peak = meterInformation.PeakValue;
            //here you can check peak value and implement your wishes