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SemanticResultKey Class

Associates a key string with SemanticResultValue values to define the SemanticValue objects.

System.Object
  Microsoft.Speech.Recognition.SemanticResultKey

Namespace:  Microsoft.Speech.Recognition
Assembly:  Microsoft.Speech (in Microsoft.Speech.dll)

public class SemanticResultKey

The basic unit of semantic expression under the Microsoft Speech Platform SDK 11 is the SemanticValue, which is a key-value pair.

The SemanticResultKey object tags SemanticResultValue instances contained in GrammarBuilder objects and strings so that the values can readily be accessed from SemanticValue instances following recognition.

You can use SemanticResultValue and SemanticResultKey objects, in conjunction with GrammarBuilder and Choices objects, to define the semantic structure for a speech recognition grammar. To access the semantic information in a recognition result, obtain a SemanticValue instance through the Semantics property on RecognizedPhrase.

For more information about using SemanticResultValue and SemanticResultKey objects, see Add Semantics to a GrammarBuilder Grammar (Microsoft.Speech) and Use a SemanticResultKey to Extract a SemanticResultValue (Microsoft.Speech).

The following example creates a Grammar to recognize password input of the form "My password is …", where the actual input is matched with a wildcard.

The wildcard is tagged with a semantic key, and the SpeechRecognized handler checks for the presence of this tag to verify that a password input has occurred.

private void pwdGrammar() 
{
  GrammarBuilder pwdBuilder = new GrammarBuilder("My Password is");
  GrammarBuilder wildcardBuilder = new GrammarBuilder();
  wildcardBuilder.AppendWildcard();
  SemanticResultKey wildcardKey= new SemanticResultKey("Password", wildcardBuilder);
  pwdBuilder+=wildcardKey;
  Grammar grammar = new Grammar(pwdBuilder);
  grammar.Name = "Password input";
  
  grammar.SpeechRecognized +=
    delegate(object sender, SpeechRecognizedEventArgs eventArgs) 
    {
      SemanticValue semantics = eventArgs.Result.Semantics;
      RecognitionResult result=eventArgs.Result;

      if (!semantics.ContainsKey("Password")) 
      {
        SpeechUI.SendTextFeedback(eventArgs.Result, "No Password Provided", false);
      }
      else
      {
        RecognizedAudio pwdAudio = 
            result.GetAudioForWordRange(result.Words[3],
            result.Words[result.Words.Count - 1]);
        MemoryStream pwdMemoryStream = new MemoryStream();
        pwdAudio.WriteToAudioStream(pwdMemoryStream);
        if (!IsValidPwd(pwdMemoryStream)) 
        {
          string badPwd = System.IO.Path.GetTempPath() +
                   "BadPwd" +
                   (new Random()).Next().ToString() +
                   ".wav";
          FileStream waveStream = new FileStream(badPwd, FileMode.Create);
          pwdAudio.WriteToWaveStream(waveStream);
          waveStream.Flush();
          waveStream.Close();
          SpeechUI.SendTextFeedback(eventArgs.Result, "Invalid Password", false);

        }
      }
    };

  grammar.Enabled = true;
  _recognizer.LoadGrammar(grammar);
  UpdateGrammarTree(_grammarTreeView, _recognizer);
}

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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