SpeechRecognitionRejectedEventArgs Class

SpeechRecognitionRejectedEventArgs Class

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


public class SpeechRecognitionRejectedEventArgs : RecognitionEventArgs


Gets the recognition result data associated with the speech recognition event.(Inherited from RecognitionEventArgs.)


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

The SpeechRecognitionRejected event is raised by the SpeechRecognizer and SpeechRecognitionEngine classes.

SpeechRecognitionRejected events are generated by a speech recognition engine when none of the alternates from a recognition operation have a high enough confidence score to be accepted. Detailed information about rejected phrases is available through the Result property.

SpeechRecognitionRejectedEventArgs derives from RecognitionEventArgs.

The following example recognizes phrases such as "Display the list of artists in the jazz category" or "Display albums gospel". The example uses a handler for the SpeechRecognitionRejected event to display a notification in the console when the speech input cannot be matched to the contents of the grammar with sufficient confidence to produce a successful recognition.

using System;
using System.Speech.Recognition;

namespace SampleRecognition
  class Program
    static void Main(string[] args)

    // Initialize a shared speech recognition engine.
      using (SpeechRecognizer recognizer =
         new SpeechRecognizer())

        // Create a grammar.
        //  Create lists of alternative choices.
        Choices listTypes = new Choices(new string[] { "albums", "artists" });
        Choices genres = new Choices(new string[] { 
          "blues", "classical", "gospel", "jazz", "rock" });

        //  Create a GrammarBuilder object and assemble the grammar components.
        GrammarBuilder mediaMenu = new GrammarBuilder("Display");
        mediaMenu.Append("the list of", 0, 1);
        mediaMenu.Append("in the", 0, 1);
        mediaMenu.Append("category", 0, 1);

        //  Build a Grammar object from the GrammarBuilder.
        Grammar mediaMenuGrammar = new Grammar(mediaMenu);
        mediaMenuGrammar.Name = "Media Chooser";

        // Attach event handlers.
        recognizer.LoadGrammarCompleted +=
          new EventHandler<LoadGrammarCompletedEventArgs>(recognizer_LoadGrammarCompleted);
        recognizer.SpeechRecognized +=
          new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);
        recognizer.SpeechRecognitionRejected += 
          new EventHandler<SpeechRecognitionRejectedEventArgs>(recognizer_SpeechRecognitionRejected);

        // Load the grammar object to the recognizer.

        // Keep the console window open.

    // Handle the SpeechRecognitionRejected event.
    static void recognizer_SpeechRecognitionRejected(object sender, SpeechRecognitionRejectedEventArgs e)
      Console.WriteLine("Speech input was rejected.");
      foreach (RecognizedPhrase phrase in e.Result.Alternates)
        Console.WriteLine("  Rejected phrase: " + phrase.Text);
        Console.WriteLine("  Confidence score: " + phrase.Confidence);

    // Handle the LoadGrammarCompleted event.
    static void recognizer_LoadGrammarCompleted(object sender, LoadGrammarCompletedEventArgs e)
      Console.WriteLine("Grammar loaded: " + e.Grammar.Name);

    // Handle the SpeechRecognized event.
    static void recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
      Console.WriteLine("Speech recognized: " + e.Result.Text);

.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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