private static void SetMasterMute(bool isMute, ref RPIData data) { MMDevice device = GetDefaultDevice(); AudioEndpointVolume Endpointvolume = AudioEndpointVolume.FromDevice(device); Endpointvolume.SetMuteNative(isMute, new Guid()); if (isMute == false) { for (int i = 0; i < data.Programs.Count; i++) { data.Programs[i].IsMute = false; } } }