如何在Microsoft.Speech中使用DTMFRecognitionEngine类

看来这是不可能的。我什至还获得了DtmfRecognitionEngine的私有_engine，它是SpeechRecognitionEngine的包装器，没有运气就调用了它的SetInputToWaveFile。显然，向DtmfRecognitionEngine发出提示音的唯一方法是调用AddTone（）。我提供了一个示例语法文件和一些可以使用的源代码。有趣的是，如果取消对dre.AddTone（）的注释，则将看到sre的事件和dre的事件都被触发。

将呼叫切换到sre.RecognizeAsync（）无济于事。

看来您需要一个不同的库...

PinGrammar.xml

<?xml version="1.0"?>
<grammar mode="dtmf" version="1.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://www.w3.org/2001/06/grammar 
                             http://www.w3.org/TR/speech-grammar/grammar.xsd"
         xmlns="http://www.w3.org/2001/06/grammar"
         root="pin">

  <rule id="digit">
    <one-of>
      <item> 0 </item>
      <item> 1 </item>
      <item> 2 </item>
      <item> 3 </item>
      <item> 4 </item>
      <item> 5 </item>
      <item> 6 </item>
      <item> 7 </item>
      <item> 8 </item>
      <item> 9 </item>
    </one-of>
  </rule>

  <rule id="pin" scope="public">
    <one-of>
      <item>
        <item repeat="4">
          <ruleref uri="#digit"/>
        </item>
        #
      </item>
      <item>
        * 9
      </item>
    </one-of>
  </rule>

</grammar>

来源：

using Microsoft.Speech.Recognition;
using System.Reflection;

namespace DTMF_Recognition
{
    class Program
    {
        static void Main(string[] args)
        {
            Grammar grammar = null;
            grammar = new Grammar("PinGrammar.xml");

            DtmfRecognitionEngine dre = new DtmfRecognitionEngine();
            dre.DtmfRecognized += dre_DtmfRecognized;

            FieldInfo field = typeof(DtmfRecognitionEngine).GetField("_engine", BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);
            var wrapper = field.GetValue(dre);
            FieldInfo engineField = wrapper.GetType().GetField("_engine", BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);
            SpeechRecognitionEngine sre = (SpeechRecognitionEngine)engineField.GetValue(wrapper);

            dre.DtmfHypothesized += dre_DtmfHypothesized;
            dre.DtmfRecognitionRejected += dre_DtmfRecognitionRejected;
            dre.RecognizeCompleted += dre_RecognizeCompleted;
            dre.LoadGrammar(grammar);

            //dre.AddTone(DtmfTone.One);
            //dre.AddTone(DtmfTone.Two);
            //dre.AddTone(DtmfTone.Three);
            //dre.AddTone(DtmfTone.Four);
            //dre.AddTone(DtmfTone.Hash);

            sre.SetInputToWaveFile(@"C:\Users\Clay Ver Valen\Desktop\3.wav");
            sre.SpeechHypothesized += sre_SpeechHypothesized;
            sre.SpeechDetected += sre_SpeechDetected;
            sre.SpeechRecognitionRejected += sre_SpeechRecognitionRejected;

            dre.RecognizeAsync();
            System.Threading.Thread.Sleep(30000);
        }

        static void sre_SpeechRecognitionRejected(object sender, SpeechRecognitionRejectedEventArgs e)
        {
            int i = 1;
        }

        static void sre_SpeechHypothesized(object sender, SpeechHypothesizedEventArgs e)
        {
            int i = 1;
        }

        static void sre_SpeechDetected(object sender, SpeechDetectedEventArgs e)
        {
            int i = 1;
        }

        static void dre_DtmfRecognitionRejected(object sender, DtmfRecognitionRejectedEventArgs e)
        {
            int i = 1;
        }

        static void dre_DtmfHypothesized(object sender, DtmfHypothesizedEventArgs e)
        {
            int i = 1;
        }

        static void dre_RecognizeCompleted(object sender, DtmfRecognizeCompletedEventArgs e)
        {
            int i = 1;
        }

        static void dre_DtmfRecognized(object sender, DtmfRecognizedEventArgs e)
        {
            int i = 1;
        }
    }
}