取消Windows Phone 8语音识别会话？

Question

我有一个Windows Phone 8应用程序，该应用程序使用SpeechRecognizer类（ 而不是 SpeechRecognizerUI）来进行语音识别。 如何取消正在进行的会话？ 我在SpeechRecognizer类中看不到cancel或Stop方法。

更新 ：我想基于此MSDN线程为mparkuk的答案提供上下文：

SpeechRecognizer.Settings.InitialSilenceTimeout无法正常工作

取消语音识别操作的方法是维持对识别器IAsyncOperation调用返回的IAsyncOperation的引用，而不是通过直接等待 RecoAsync（）调用以获得识别结果来“丢弃”它。 我将在下面包含代码，以防线程随着时间的流逝而丢失。 取消语音识别会话的要点是调用IAsyncOperation.Cancel（）方法。

    private const int SpeechInputTimeoutMSEC = 10000;

    private SpeechRecognizer CreateRecognizerAndLoadGrammarAsync(string fileName, Uri grammarUri, out Task grammarLoadTask)
    {
        // Create the recognizer and start loading grammars
        SpeechRecognizer reco = new SpeechRecognizer();
        // @@BUGBUG: Set the silence detection to twice the configured time - we cancel it from the thread
        reco.Settings.InitialSilenceTimeout = TimeSpan.FromMilliseconds(2 * SpeechInputTimeoutMSEC);
        reco.AudioCaptureStateChanged += recognizer_AudioCaptureStateChanged;
        reco.Grammars.AddGrammarFromUri(fileName, grammarUri);

        // Start pre-loading grammars to minimize reco delays:
        reco.PreloadGrammarsAsync();
        return reco;
    }

    /// <summary>
    /// Recognize async
    /// </summary>
    public async void RecognizeAsync()
    {
        try
        {
            // Start recognition asynchronously
            this.currentRecoOperation = this.recognizer.RecognizeAsync();

            // @@BUGBUG: Add protection code and handle speech timeout programmatically
            this.SpeechBugWorkaround_RunHangProtectionCode(this.currentRecoOperation);

            // Wait for the reco to complete (or get cancelled)
            SpeechRecognitionResult result = await this.currentRecoOperation;
            this.currentRecoOperation = null;

    // Get the results
    results = GetResults(result);
            this.CompleteRecognition(results, speechError);
        }
        catch (Exception ex)
        {
    // error
            this.CompleteRecognition(null, ex);
        }

        // Restore the recognizer for next operation if necessary
        this.ReinitializeRecogizerIfNecessary();
    }

    private void SpeechBugWorkaround_RunHangProtectionCode(IAsyncOperation<SpeechRecognitionResult> speechRecoOp)
    {
        ThreadPool.QueueUserWorkItem(delegate(object s)
        {
            try
            {
                bool cancelled = false;
                if (false == this.capturingEvent.WaitOne(3000) && speechRecoOp.Status == AsyncStatus.Started)
                {
                    cancelled = true;
                    speechRecoOp.Cancel();
                }

                // If after 10 seconds we are still running - cancel the operation.
                if (!cancelled)
                {
                    Thread.Sleep(SpeechInputTimeoutMSEC);
                    if (speechRecoOp.Status == AsyncStatus.Started)
                    {
                        speechRecoOp.Cancel();
                    }
                }
            }
            catch (Exception) { /* TODO: Add exception handling code */}
        }, null);
    }

    private void ReinitializeRecogizerIfNecessary()
    {
        lock (this.sync)
        {
            // If the audio capture event was not raised, the recognizer hang -> re-initialize it.
            if (false == this.capturingEvent.WaitOne(0))
            {
                this.recognizer = null;
                this.CreateRecognizerAndLoadGrammarAsync(...);
            }
        }
    }

    /// <summary>
    /// Handles audio capture events so we can tell the UI thread we are listening...
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="args"></param>
    private void recognizer_AudioCaptureStateChanged(SpeechRecognizer sender, SpeechRecognizerAudioCaptureStateChangedEventArgs args)
    {
        if (args.State == SpeechRecognizerAudioCaptureState.Capturing)
        {
            this.capturingEvent.Set(); 
        }
    }

-------------------------------------来自MSDN的主题--------- ----------

图片来源：Mark Chamberlain高级升级工程师| Microsoft开发人员支持| Windows Phone 8

关于取消机制，这是开发人员的一些建议代码。

RecognizeAsync返回的IAsyncOperation具有取消功能。

你必须：

1）将初始静音超时设置为较大的值（例如：两倍于所需的语音输入超时，在我的情况下为10秒）。

2）存储this.currentRecoOperation = this.recognizer.RecognizeAsync（）;

3）如有必要，请在10秒后启动辅助线程以取消操作。 我不想冒险，所以我还添加了代码，以在检测到挂起时重新初始化所有内容。 通过查看音频捕获状态在开始识别后的几秒钟内是否已更改为“正在捕获”来完成此操作。

Answer 1

你看过这个话题吗？

SpeechRecognizer.Settings.InitialSilenceTimeout无法正常工作