SpeechRecognizer.LoadGrammarCompleted Event


Occurs when the recognizer finishes the asynchronous loading of a speech recognition grammar.

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

public event EventHandler<LoadGrammarCompletedEventArgs> LoadGrammarCompleted

The recognizer's LoadGrammarAsync method initiates an asynchronous operation. The recognizer raises the LoadGrammarCompleted event when it completes the operation. To get the Grammar object that the recognizer loaded, use the Grammar property of the associated LoadGrammarCompletedEventArgs. To get the current Grammar objects the recognizer has loaded, use the recognizer's Grammars property.

When you create a delegate for a LoadGrammarCompleted event, 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 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. Handlers for the recognizer's LoadGrammarCompleted and SpeechRecognized events write to the console the name of the grammar that was used to perform the recognition and the text of the recognition result, respectively.

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", "yeah}" });
        SemanticResultValue yesValue =
            new SemanticResultValue(yesChoices, (bool)true);
        Choices noChoices = new Choices(new string[] { "no", "nope", "neah" });
        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.

        // Keep the console window open.

    // Handle the SpeechRecognized event.
    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");

    // 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");

.NET Framework
Available since 3.0
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