StateChangedEventArgs Class

Definition

public ref class StateChangedEventArgs : EventArgs

public class StateChangedEventArgs : EventArgs

type StateChangedEventArgs = class
    inherit EventArgs

Public Class StateChangedEventArgs
Inherits EventArgs

Inheritance

Object

EventArgs

StateChangedEventArgs

Examples

The following example creates a shared speech recognizer, and then creates two types of grammars for recognizing specific words and for accepting free dictation. The example asynchronously loads all the created grammars to the recognizer. A handler for the StateChanged event uses the EmulateRecognizeAsync method to put Windows Recognition in "listening" mode.

using System;  
using System.Speech.Recognition;  

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

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

      // Add a handler for the LoadGrammarCompleted event.  
      recognizer.LoadGrammarCompleted += new EventHandler<LoadGrammarCompletedEventArgs>(recognizer_LoadGrammarCompleted);  

      // Add a handler for the SpeechRecognized event.  
      recognizer.SpeechRecognized += new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);  

      // Add a handler for the StateChanged event.  
      recognizer.StateChanged += new EventHandler<StateChangedEventArgs>(recognizer_StateChanged);  

      // Create "yesno" grammar.  
      Choices yesChoices = new Choices(new string[] { "yes", "yup", "yah}" });  
      SemanticResultValue yesValue =  
          new SemanticResultValue(yesChoices, (bool)true);  
      Choices noChoices = new Choices(new string[] { "no", "nope", "nah" });  
      SemanticResultValue noValue = new SemanticResultValue(noChoices, (bool)false);  
      SemanticResultKey yesNoKey =  
          new SemanticResultKey("yesno", new Choices(new GrammarBuilder[] { yesValue, noValue }));  
      Grammar yesnoGrammar = new Grammar(yesNoKey);  
      yesnoGrammar.Name = "yesNo";  

      // Create "done" grammar.  
      Grammar doneGrammar =  
        new Grammar(new Choices(new string[] { "done", "exit", "quit", "stop" }));  
      doneGrammar.Name = "Done";  

      // Create dictation grammar.  
      Grammar dictation = new DictationGrammar();  
      dictation.Name = "Dictation";  

      // Load grammars to the recognizer.  
      recognizer.LoadGrammarAsync(yesnoGrammar);  
      recognizer.LoadGrammarAsync(doneGrammar);  
      recognizer.LoadGrammarAsync(dictation);  

      // Keep the console window open.  
      Console.ReadLine();  
    }  

    // Put the shared speech recognizer into "listening" mode.  
    static void  recognizer_StateChanged(object sender, StateChangedEventArgs e)  
    {  
     if (e.RecognizerState != RecognizerState.Stopped)  
      {  
        recognizer.EmulateRecognizeAsync("Start listening");  
      }  
    }  

    // Write the grammar name and the text of the recognized phrase to the console.  
    static void  recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)  
    {  
     Console.WriteLine("Grammar({0}): {1}", e.Result.Grammar.Name, e.Result.Text);  

      // Add event handler code here.  
    }  

    // Handle the LoadGrammarCompleted event.  
    static void  recognizer_LoadGrammarCompleted(object sender, LoadGrammarCompletedEventArgs e)  
    {  
     string grammarName = e.Grammar.Name;  
      bool grammarLoaded = e.Grammar.Loaded;  
      if (e.Error != null)  
      {  
        Console.WriteLine("LoadGrammar for {0} failed with a {1}.",  
        grammarName, e.Error.GetType().Name);  
      }  

      // Add exception handling code here.  
      Console.WriteLine("Grammar {0} {1} loaded.",  
      grammarName, (grammarLoaded) ? "is" : "is not");  
    }  
  }  
}  

Remarks

The StateChanged event is raised by the SpeechRecognizer class. StateChangedEventArgs derives from EventArgs and is passed to handlers for StateChanged events.

State is a read-only property. A shared speech recognizer's state cannot be changed programmatically. Users can change a shared speech recognizer's state using the Speech Recognition user interface (UI) or through the Speech Recognition member of the Windows Control Panel.

Both the On and Sleep settings in the Speech Recognition UI correspond to the Listening state. The Off setting in the Speech Recognition UI corresponds to Stopped.

Properties

Methods

Applies to

See also

• StateChanged
• RecognizerState