Metodo RecognizerContext.BackgroundRecognizeWithAlternates

Articolo
10/29/2008

Aggiornamento: novembre 2007

Fa in modo che l'oggetto Recognizer riconosca l'insieme Strokes associato e generi un evento RecognitionWithAlternates, con i dati dell'applicazione associati, quando il riconoscimento è completo.

Spazio dei nomi: Microsoft.Ink
Assembly: Microsoft.Ink (in Microsoft.Ink.dll)

Sintassi

'Dichiarazione
Public Sub BackgroundRecognizeWithAlternates
'Utilizzo
Dim instance As RecognizerContext

instance.BackgroundRecognizeWithAlternates()

public void BackgroundRecognizeWithAlternates()

public:
void BackgroundRecognizeWithAlternates()

public void BackgroundRecognizeWithAlternates()

public function BackgroundRecognizeWithAlternates()

Note

Questo metodo specifica che il riconoscimento dell'input penna viene eseguito in modo asincrono.

Per eseguire il riconoscimento che include solo la prima alternativa, chiamare il metodo BackgroundRecognize.

Se il sistema di riconoscimento non riconosce nessuna alternativa, l'evento RecognitionWithAlternates non viene generato.

Esempi

In questo esempio viene riconosciuto automaticamente ogni tratto eseguito in un oggetto InkOverlay e vengono visualizzati i risultati del riconoscimento (incluse le alternative).

All'avvio dell'applicazione, viene creata un'istanza dell'oggetto RecognizerContext e vengono assegnati i gestori eventi.

' create a new RecognizerContext object
' the object's Strokes property is initialized to null
mRecognizerContext = New RecognizerContext()
' assign the Strokes property by creating a fresh Strokes collection 
mRecognizerContext.Strokes = mInkOverlay.Ink.CreateStrokes()
' subscribe to the Strokes event. It is during this event
' that we can add strokes to the RecognizerContext
AddHandler mInkOverlay.Stroke, New InkCollectorStrokeEventHandler(AddressOf mInkOverlay_Stroke1)
' subscribe to the the RecognitionWithAlternates event. 
' This event is fired when background recognition is complete, 
' and recognition results (with alternates) are available
AddHandler mRecognizerContext.RecognitionWithAlternates, _
     New RecognizerContextRecognitionWithAlternatesEventHandler(AddressOf mRecognizerContext_RecognitionWithAlternates)

// create a new RecognizerContext object
// the object's Strokes property is initialized to null
mRecognizerContext = new RecognizerContext();
// assign the Strokes property by creating a fresh Strokes collection 
mRecognizerContext.Strokes = mInkOverlay.Ink.CreateStrokes();
// subscribe to the Strokes event. It is during this event
// that we can add strokes to the RecognizerContext
mInkOverlay.Stroke += new InkCollectorStrokeEventHandler(mInkOverlay_Stroke1);
// subscribe to the the RecognitionWithAlternates event. 
// This event is fired when background recognition is complete, 
// and recognition results (with alternates) are available
mRecognizerContext.RecognitionWithAlternates += 
    new RecognizerContextRecognitionWithAlternatesEventHandler(mRecognizerContext_RecognitionWithAlternates);

Quando viene generato l'evento Stroke (in risposta al completamento di un tratto da parte dell'utente), il tratto appena creato viene aggiunto all'insieme Strokes dell'oggetto RecognizerContext e viene chiamato il metodo BackgroundRecognizeWithAlternates.

Private Sub mInkOverlay_Stroke1(ByVal sender As Object, ByVal e As InkCollectorStrokeEventArgs)
    ' in case background recognition is still occurring, stop it
    mRecognizerContext.StopBackgroundRecognition()
    ' add the stroke, and start recognition
    mRecognizerContext.Strokes.Add(e.Stroke)
    mRecognizerContext.BackgroundRecognizeWithAlternates()
End Sub

private void mInkOverlay_Stroke1(object sender, InkCollectorStrokeEventArgs e)
{
    // in case background recognition is still occurring, stop it
    mRecognizerContext.StopBackgroundRecognition();
    // add the stroke, and start recognition
    mRecognizerContext.Strokes.Add(e.Stroke);
    mRecognizerContext.BackgroundRecognizeWithAlternates();
}

Al termine del riconoscimento in background, viene generato l'evento RecognitionWithAlternates. Durante la gestione di questo evento, i risultati del riconoscimento (incluse le alternative) vengono collocati in una casella di riepilogo.

' event fires when recognition results (with alternates) are ready
Private Sub mRecognizerContext_RecognitionWithAlternates(ByVal sender As Object, _
            ByVal e As RecognizerContextRecognitionWithAlternatesEventArgs)
    ' when updating a control, must use Invoke() since controls are
    ' not thread safe and recognition occurs on a different thread
    If Me.InvokeRequired Then
        ' recursively call this method via Invoke()
        Me.Invoke( _
            New RecognizerContextRecognitionWithAlternatesEventHandler(AddressOf mRecognizerContext_RecognitionWithAlternates), _
            New Object() {sender, e} _
        )
        Return
    End If
    If RecognitionStatus.NoError = e.RecognitionStatus Then
        ' show the top alternate
        listBoxRecognitionResults.Items.Add("TOP:" + e.Result.TopAlternate.ToString())
        ' get the rest of the alternates
        Dim allAlternates As RecognitionAlternates = e.Result.GetAlternatesFromSelection()
        ' show each of the other alternates
        For Each oneAlternate As RecognitionAlternate In allAlternates
            listBoxRecognitionResults.Items.Add("ALT:" + oneAlternate.ToString())
        Next
    End If
End Sub

// event fires when recognition results (with alternates) are ready
private void mRecognizerContext_RecognitionWithAlternates(object sender, RecognizerContextRecognitionWithAlternatesEventArgs e)
{
    // when updating a control, must use Invoke() since controls are
    // not thread safe and recognition occurs on a different thread
    if (this.InvokeRequired)
    {
        // recursively call this method via Invoke()
        this.Invoke(
            new RecognizerContextRecognitionWithAlternatesEventHandler(mRecognizerContext_RecognitionWithAlternates),
            new object[] { sender, e }
            );
        return;
    }
    if (RecognitionStatus.NoError == e.RecognitionStatus)
    {
        // show the top alternate
        listBoxRecognitionResults.Items.Add("TOP:" + e.Result.TopAlternate.ToString());
        // get the rest of the alternates
        RecognitionAlternates allAlternates = e.Result.GetAlternatesFromSelection();
        // show each of the other alternates
        foreach (RecognitionAlternate oneAlternate in allAlternates)
        {
            listBoxRecognitionResults.Items.Add("ALT:" + oneAlternate.ToString());
        }
    }
}

Piattaforme

Windows Vista

.NET Framework e .NET Compact Framework non supportano tutte le versioni di ciascuna piattaforma. Per un elenco delle versioni supportate, vedere Requisiti di sistema di .NET Framework.