public DelegateCommand PlayCommand { get; private set; }
 public DelegateCommand StopCommand { get; private set; }
 public DelegateCommand RecordCommand { get; private set; }
 public DelegateCommand PauseCommand { get; private set; }

 private AudioGraph audioGraph;
 private DeviceInformation selectedDevice;
 private TimeSpan duration;
 private TimeSpan position;
 private AudioFileOutputNode fileOutputNode;
 private AudioFileInputNode fileInputNode;
 private AudioDeviceOutputNode deviceOutputNode;
 private AudioDeviceInputNode deviceInputNode;

 private async void Record()
    {
        if (audioGraph == null)
        {
            var settings = new AudioGraphSettings(AudioRenderCategory.Media);
            settings.EncodingProperties = recordingFormat.Audio;
            var res = await AudioGraph.CreateAsync(settings);
            if (res.Status != AudioGraphCreationStatus.Success)
            {
                Diagnostics += $"Audio Graph Creation Error: {res.Status}rn";
                return;
            }

            audioGraph = res.Graph;
            audioGraph.UnrecoverableErrorOccurred += OnAudioGraphError;
        }

        if (deviceInputNode == null)
        {
            var res = await audioGraph.CreateDeviceInputNodeAsync(MediaCategory.Speech,
                recordingFormat.Audio, SelectedInputDevice);
            // if you get AudioDeviceNodeCreationStatus.AccessDenied -
            //remember to add microphone capabilities
            if (res.Status != AudioDeviceNodeCreationStatus.Success)
            {
                Diagnostics += $"Device Input Node Error: {res.Status}rn";
                return;
            }

            deviceInputNode = res.DeviceInputNode;
        }

        var outputStorageFile = await SelectOutputFile();
        if (outputStorageFile != null)
        {
            var res = await audioGraph.CreateFileOutputNodeAsync(
                outputStorageFile, recordingFormat);
            if (res.Status != AudioFileNodeCreationStatus.Success)
            {
                Diagnostics += $"Output File Error: {res.Status}rn";
                return;
            }

            fileOutputNode = res.FileOutputNode;

            // construct the graph
            deviceInputNode.AddOutgoingConnection(fileOutputNode);
        }

        audioGraph.Start();
        EnableCommands(true);
        Diagnostics += "Started recordingrn";
    }