SpeechRecognitionEngine.RequestRecognizerUpdate Method

Definition

Namespace:

System.Speech.Recognition

Assembly:

System.Speech.dll

Package:

System.Speech v8.0.0

Requests that the recognizer pauses to update its state.

Overloads

RequestRecognizerUpdate(Object, TimeSpan)	Requests that the recognizer pauses to update its state and provides an offset and a user token for the associated event.
RequestRecognizerUpdate(Object)	Requests that the recognizer pauses to update its state and provides a user token for the associated event.
RequestRecognizerUpdate()	Requests that the recognizer pauses to update its state.

Remarks

Use this method to synchronize changes to the recognizer. For example, if you load or unload a speech recognition grammar while the recognizer is processing input, use this method and the RecognizerUpdateReached event to synchronize your application behavior with the state of the recognizer.

When this method is called, the recognizer pauses or completes asynchronous operations and generates a RecognizerUpdateReached event. A RecognizerUpdateReached event handler can then modify the state of the recognizer in between recognition operations. When handling RecognizerUpdateReached events, the recognizer pauses until the event handler returns.

Note

If the input to the recognizer is changed before the recognizer raises the RecognizerUpdateReached event, the request is discarded.

When this method is called:

• If the recognizer is not processing input, the recognizer immediately generates the RecognizerUpdateReached event.

• If the recognizer is processing input that consists of silence or background noise, the recognizer pauses the recognition operation and generates the RecognizerUpdateReached event.

• If the recognizer is processing input that does not consist of silence or background noise, the recognizer completes the recognition operation and then generates the RecognizerUpdateReached event.

While the recognizer is handling the RecognizerUpdateReached event:

• The recognizer does not process input, and the value of the RecognizerAudioPosition property remains the same.

• The recognizer continues to collect input, and the value of the AudioPosition property can change.

RequestRecognizerUpdate(Object, TimeSpan)

Source:

SpeechRecognitionEngine.cs

Requests that the recognizer pauses to update its state and provides an offset and a user token for the associated event.

public:
 void RequestRecognizerUpdate(System::Object ^ userToken, TimeSpan audioPositionAheadToRaiseUpdate);

public void RequestRecognizerUpdate (object userToken, TimeSpan audioPositionAheadToRaiseUpdate);

member this.RequestRecognizerUpdate : obj * TimeSpan -> unit

Public Sub RequestRecognizerUpdate (userToken As Object, audioPositionAheadToRaiseUpdate As TimeSpan)

Parameters

userToken

Object

User-defined information that contains information for the operation.

audioPositionAheadToRaiseUpdate

TimeSpan

The offset from the current AudioPosition to delay the request.

Remarks

The recognizer does not initiate the recognizer update request until the recognizer's RecognizerAudioPosition equals the current AudioPosition plus audioPositionAheadToRaiseUpdate.

When the recognizer generates the RecognizerUpdateReached event, the UserToken property of the RecognizerUpdateReachedEventArgs contains the value of the userToken parameter.

See also

• RecognizerUpdateReached
• RecognizerAudioPosition
• AudioPosition

RequestRecognizerUpdate(Object)

Source:

SpeechRecognitionEngine.cs

Requests that the recognizer pauses to update its state and provides a user token for the associated event.

public:
 void RequestRecognizerUpdate(System::Object ^ userToken);

public void RequestRecognizerUpdate (object userToken);

member this.RequestRecognizerUpdate : obj -> unit

Public Sub RequestRecognizerUpdate (userToken As Object)

Parameters

userToken

Object

User-defined information that contains information for the operation.

Remarks

When the recognizer generates the RecognizerUpdateReached event, the UserToken property of the RecognizerUpdateReachedEventArgs contains the value of the userToken parameter.

To specify an audio position offset, use the RequestRecognizerUpdate method.

See also

• RecognizerUpdateReached
• RecognizerAudioPosition
• AudioPosition

RequestRecognizerUpdate()

Source:

SpeechRecognitionEngine.cs

Requests that the recognizer pauses to update its state.

public:
 void RequestRecognizerUpdate();

public void RequestRecognizerUpdate ();

member this.RequestRecognizerUpdate : unit -> unit

Public Sub RequestRecognizerUpdate ()

Examples

The following example shows a console application that loads and unloads Grammar objects. The application uses the RequestRecognizerUpdate method to request the speech recognition engine to pause so it can receive an update. The application then loads or unloads a Grammar object.

At each update, a handler for RecognizerUpdateReached event writes the name and status of the currently loaded Grammar objects to the console. As grammars are loaded and unloaded, the application first recognizes the names of farm animals, then the names of farm animals and the names of fruits, then only the names of fruits.

using System;  
using System.Speech.Recognition;  
using System.Collections.Generic;  
using System.Threading;  

namespace SampleRecognition  
{  
  class Program  
  {  
    private static SpeechRecognitionEngine recognizer;  
    public static void Main(string[] args)  
    {  

      // Initialize an in-process speech recognition engine and configure its input.  
      using (recognizer = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US")))  
      {  
        recognizer.SetInputToDefaultAudioDevice();  

        // Create the first grammar - Farm.  
        Choices animals = new Choices(new string[] { "cow", "pig", "goat" });  
        GrammarBuilder farm = new GrammarBuilder(animals);  
        Grammar farmAnimals = new Grammar(farm);  
        farmAnimals.Name = "Farm";  

        // Create the second grammar - Fruit.  
        Choices fruit = new Choices(new string[] { "apples", "peaches", "oranges" });  
        GrammarBuilder favorite = new GrammarBuilder(fruit);  
        Grammar favoriteFruit = new Grammar(favorite);  
        favoriteFruit.Name = "Fruit";  

        // Attach event handlers.  
        recognizer.SpeechRecognized +=  
          new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);  
        recognizer.RecognizerUpdateReached +=  
          new EventHandler<RecognizerUpdateReachedEventArgs>(recognizer_RecognizerUpdateReached);  
        recognizer.SpeechRecognitionRejected +=  
          new EventHandler<SpeechRecognitionRejectedEventArgs>(recognizer_SpeechRecognitionRejected);  

        // Load the Farm grammar.  
        recognizer.LoadGrammar(farmAnimals);  

        // Start asynchronous, continuous recognition.  
        recognizer.RecognizeAsync(RecognizeMode.Multiple);  
        Console.WriteLine("Starting asynchronous, continuous recognition");  
        Console.WriteLine("  Farm grammar is loaded and enabled.");  

        // Pause to recognize farm animals.  
        Thread.Sleep(7000);  
        Console.WriteLine();  

        // Request an update and load the Fruit grammar.  
        recognizer.RequestRecognizerUpdate();  
        recognizer.LoadGrammarAsync(favoriteFruit);  
        Thread.Sleep(7000);  

        // Request an update and unload the Farm grammar.  
        recognizer.RequestRecognizerUpdate();  
        recognizer.UnloadGrammar(farmAnimals);  
        Thread.Sleep(7000);  
      }  

      // Keep the console window open.  
      Console.WriteLine();  
      Console.WriteLine("Press any key to exit...");  
      Console.ReadKey();  
    }  

    // At the update, get the names and enabled status of the currently loaded grammars.  
    public static void recognizer_RecognizerUpdateReached(  
      object sender, RecognizerUpdateReachedEventArgs e)  
    {  
      Console.WriteLine();  
      Console.WriteLine("Update reached:");  
      Thread.Sleep(1000);  

      string qualifier;  
      List<Grammar> grammars = new List<Grammar>(recognizer.Grammars);  
      foreach (Grammar g in grammars)  
      {  
        qualifier = (g.Enabled) ? "enabled" : "disabled";  
        Console.WriteLine("  {0} grammar is loaded and {1}.",  
        g.Name, qualifier);  
      }  
    }  

    // Write the text of the recognized phrase to the console.  
    static void recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)  
    {  
      Console.WriteLine("    Speech recognized: " + e.Result.Text);  
    }  

    // Write a message to the console when recognition fails.  
    static void recognizer_SpeechRecognitionRejected(object sender, SpeechRecognitionRejectedEventArgs e)  
    {  
      Console.WriteLine("    Recognition attempt failed");  
    }  
  }  
}  

Remarks

When the recognizer generates the RecognizerUpdateReached event, the UserToken property of the RecognizerUpdateReachedEventArgs is null.

To provide a user token, use the RequestRecognizerUpdate or RequestRecognizerUpdate method. To specify an audio position offset, use the RequestRecognizerUpdate method.

See also

• RecognizerUpdateReached
• RecognizerAudioPosition
• AudioPosition