SpeechRecognitionEngine.EmulateRecognizeCompleted Event

Raised when the SpeechRecognitionEngine finalizes an asynchronous recognition operation of emulated input.

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


Public Event EmulateRecognizeCompleted As EventHandler(Of EmulateRecognizeCompletedEventArgs)
Dim instance As SpeechRecognitionEngine
Dim handler As EventHandler(Of EmulateRecognizeCompletedEventArgs)

AddHandler instance.EmulateRecognizeCompleted, handler
public event EventHandler<EmulateRecognizeCompletedEventArgs> EmulateRecognizeCompleted


Each EmulateRecognizeAsync method begins an asynchronous recognition operation. The SpeechRecognitionEngine raises the EmulateRecognizeCompleted event when it finalizes the asynchronous operation.

The EmulateRecognizeAsync(String) operation can raise the SpeechDetected, SpeechHypothesized, SpeechRecognitionRejected, and SpeechRecognized events. The EmulateRecognizeCompleted event is the last such event that the recognizer raises for a given operation.

If emulated recognition was successful, you can access the recognition result using the either of the following:

If emulated recognition was not successful, the SpeechRecognized event is not raised and the Result will be null.


Do not call the [Dispose] method on a SpeechRecognitionEngine from within an event handler.

EmulateRecognizeCompletedEventArgs derives from AsyncCompletedEventArgs.

SpeechRecognizedEventArgs derives from RecognitionEventArgs.

When you create an EmulateRecognizeCompleted delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.


The following example is part of a console application that loads a speech recognition grammar and demonstrates asynchronous emulated input, the associated recognition results, and the associated events raised by the speech recognizer.

using System;
using Microsoft.Speech.Recognition;
using System.Threading;

namespace InProcessRecognizer
  class Program
    // Indicate whether the asynchronous emulate recognition
    // operation has completed.
    static bool completed;

    static void Main(string[] args)

      // Initialize a SpeechRecognitionEngine object.
      using (SpeechRecognitionEngine recognizer = 
        new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US")))
        // Create and load a sample grammar.
        Grammar testGrammar =
          new Grammar(new GrammarBuilder("testing testing"));
        testGrammar.Name = "Test Grammar";

        // Attach event handlers for recognition events.
        recognizer.SpeechRecognized +=
          new EventHandler<SpeechRecognizedEventArgs>(SpeechRecognizedHandler);
        recognizer.EmulateRecognizeCompleted +=
          new EventHandler<EmulateRecognizeCompletedEventArgs>(

        completed = false;

        // This EmulateRecognizeAsync call mathches the grammar
        // and generates a SpeechRecognized event.
        recognizer.EmulateRecognizeAsync("testing testing");

        // Wait for the asynchronous operation to complete.
        while (!completed)

        completed = false;

        // This EmulateRecognizeAsync call does not match the grammar
        // or generate a SpeechRecognized event.
        recognizer.EmulateRecognizeAsync("testing one two three");

        // Wait for the asynchronous operation to complete.
        while (!completed)

      Console.WriteLine("Press any key to exit...");

    // Handle the SpeechRecognized event.
    static void SpeechRecognizedHandler(
      object sender, SpeechRecognizedEventArgs e)
      if (e.Result != null)
        Console.WriteLine("Result of 1st call to EmulateRecognizeAsync = {0}",
          e.Result.Text ?? "<no text>");
        Console.WriteLine("No recognition result");

    // Handle the EmulateRecognizeCompleted event.
    static void EmulateRecognizeCompletedHandler(
      object sender, EmulateRecognizeCompletedEventArgs e)
      if (e.Result == null)
        Console.WriteLine("Result of 2nd call to EmulateRecognizeAsync = No result generated.");

      // Indicate the asynchronous operation is complete.
      completed = true;

See Also


SpeechRecognitionEngine Class

SpeechRecognitionEngine Members

Microsoft.Speech.Recognition Namespace