windows-phone-8 - Caliburn Micro和麦克风NullReferenceException

Question

我使用模式MVVM Caliburn Micro，在我的ViewModel中，我有此代码

private Microphone microphone;
private byte[] buffer;
private MemoryStream stream;

public MainViewModel()
{
    microphone = Microphone.Default;
    stream = new MemoryStream();

    DispatcherTimer dt = new DispatcherTimer();
    dt.Interval = TimeSpan.FromMilliseconds(50);
    dt.Tick += delegate
    {
        try
        {
            FrameworkDispatcher.Update();
        }
        catch { }
    };

    dt.Start();
    microphone.BufferReady += new EventHandler<EventArgs>(microphone_BufferReady);
}

void microphone_BufferReady(object sender, EventArgs e)
{
    //...
}

在这个microphone.BufferReady += new EventHandler<EventArgs>(microphone_BufferReady);
接收错误=> System.NullReferenceException:对象引用未设置为对象的实例

Answer 1

WMAppManifest.xml中是否启用了ID_CAP_MICROPHONE功能？如果未启用Microphone.Default，则返回NULL。