LoadGrammarCompletedEventArgs Class


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Provides data for the LoadGrammarCompleted event of a SpeechRecognizer or SpeechRecognitionEngine object.

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


public class LoadGrammarCompletedEventArgs : AsyncCompletedEventArgs


Gets a value indicating whether an asynchronous operation has been canceled.(Inherited from AsyncCompletedEventArgs.)


Gets a value indicating which error occurred during an asynchronous operation.(Inherited from AsyncCompletedEventArgs.)


The Grammar object that has completed loading.


Gets the unique identifier for the asynchronous task.(Inherited from AsyncCompletedEventArgs.)


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.)


Raises a user-supplied exception if an asynchronous operation failed.(Inherited from AsyncCompletedEventArgs.)


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

An instance of LoadGrammarCompletedEventArgs is created when the SpeechRecognitionEngine object raises its SpeechRecognitionEngine.LoadGrammarCompleted or the SpeechRecognizer object raises its LoadGrammarCompleted event. The events are raised when calls to the LoadGrammarAsync methods complete.

To obtain information about the Grammar object that was loaded, access the Grammar property in the handler for the event.

If the recognizer encounters an exception during the operation, the Error property is set to the exception and the Loaded property of the associated Grammar may be false.

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 report the results of recognition and which grammar was used to perform the recognition.

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 the "yesno" grammar and build it into a Grammar object.
        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 the "done" grammar within the constructor of a Grammar object.
        Grammar doneGrammar =
        new Grammar(new GrammarBuilder(new Choices(new string[] { "done", "exit", "quit", "stop" })));
        doneGrammar.Name = "Done";

        // Create a 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

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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