SemanticResultKey Class

SemanticResultKey Class


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

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


public class SemanticResultKey

System_CAPS_pubmethodSemanticResultKey(String, GrammarBuilder[])

Assigns a semantic key to one or more GrammarBuilder objects used to create a speech recognition grammar.

System_CAPS_pubmethodSemanticResultKey(String, String[])

Assigns a semantic key to one or more String instances used to create a speech recognition grammar.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Returns an instance of GrammarBuilder constructed from the current SemanticResultKey instance.


Returns a string that represents the current object.(Inherited from Object.)

The basic unit of semantic expression in System.Speech is the SemanticValue, which is a key/value pair.

Using SemanticResultKey objects, you tag SemanticResultValue instances contained in GrammarBuilder objects and strings so that the values may readily be accessed from SemanticValue instances on 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 an instance of SemanticValue through the Semantics property on RecognizedPhrase.

For more information about using SemanticResultValue and SemanticResultKey objects, see and in the .610116c7-3817-40ff-857b-5d41e85110430fea1236-5261-4608-89b3-9ce9ffc22a1c198e29b8-845f-4cec-a25e-f55c0eaf46aa

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();
  SemanticResultKey wildcardKey= new SemanticResultKey("Password", wildcardBuilder);
  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);
      RecognizedAudio pwdAudio = result.GetAudioForWordRange(result.Words[3], result.Words[result.Words.Count - 1]);
      MemoryStream pwdMemoryStream = new MemoryStream();
      if (!IsValidPwd(pwdMemoryStream)) 
        string badPwd = System.IO.Path.GetTempPath() + "BadPwd" + (new Random()).Next().ToString() + ".wav";
        FileStream waveStream = new FileStream(badPwd, FileMode.Create);
        SpeechUI.SendTextFeedback(eventArgs.Result, "Invalid Password", false);

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


.NET Framework
Available since 3.0

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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