“访问被拒绝”时调用 CreateDeviceInputNodeAsync

当我按照Microsoft的文章使用AudioDeviceInputNode类时，我遇到了"AccessDenied"错误。这是我的代码：

public sealed partial class MainPage : Page {
  private AudioGraph graph = null;
  private AudioDeviceInputNode deviceInputNode = null;
  public MainPage() {
    this.InitializeComponent();
  }
  private async Task CreateAudioGraph() {
    // Create an AudioGraph with default settings
    AudioGraphSettings settings = new AudioGraphSettings(AudioRenderCategory.Media);
    CreateAudioGraphResult result = await AudioGraph.CreateAsync(settings);
    if (result.Status != AudioGraphCreationStatus.Success) {
      // Cannot create graph
      await new ContentDialog() {
        Title = "Error",
        Content = String.Format("AudioGraph Creation Error because {0}", result.Status.ToString())
      }.ShowAsync();
      return;
    }
    graph = result.Graph;
    // Create a device input node
    CreateAudioDeviceInputNodeResult inputDeviceNodeResult = await graph.CreateDeviceInputNodeAsync(Windows.Media.Capture.MediaCategory.Other);
    if (inputDeviceNodeResult.Status != AudioDeviceNodeCreationStatus.Success) {
      // Cannot create device input node
      await new ContentDialog() {
        Title = "Error",
        Content = String.Format("DeviceInputNode Creation Error because {0}", inputDeviceNodeResult.Status.ToString()),
        PrimaryButtonText = "OK",
        IsSecondaryButtonEnabled = false
      }.ShowAsync();
      return;
    }
    deviceInputNode = inputDeviceNodeResult.DeviceInputNode;
  }
  private async void button_Click(object sender, RoutedEventArgs e) {
    await CreateAudioGraph();
  }
}

但我能够运行官方样本。对这个问题有任何想法吗？