RecognizerContext.BackgroundRecognize 方法

發行項
10/29/2008

讓 Recognizer 物件辨識相關聯的 Strokes 集合，並在辨識完成時引發 Recognition 事件。

命名空間： Microsoft.Ink
組件： Microsoft.Ink (在 Microsoft.Ink.dll 中)

語法

'宣告
Public Sub BackgroundRecognize
'用途
Dim instance As RecognizerContext

instance.BackgroundRecognize()

public void BackgroundRecognize()

public:
void BackgroundRecognize()

public void BackgroundRecognize()

public function BackgroundRecognize()

備註

這個方法會指定要非同步執行筆墨辨識。若要同步辨識筆墨，請呼叫 RecognizerContext.Recognize 方法。

這個方法只能辨識最佳結果字串。這個方法並不會建立 RecognitionAlternate 物件。若要執行會建立可用替代項目清單的辨識，請呼叫 BackgroundRecognizeWithAlternates 方法。

如果辨識器不會辨識任何項目，則不會引發 Recognition 事件。

範例

在這個範例中，會自動辨識 InkOverlay 物件中所建立的每個筆劃，並顯示辨識結果。

在應用程式啟動期間，會具現化 RecognizerContext 物件並指派事件處理常式。

' 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_Stroke2)
' subscribe to the the Recognition event. 
' This event is fired when background recognition is complete, 
' and recognition results (without alternates) are available
AddHandler mRecognizerContext.Recognition, _
        New RecognizerContextRecognitionEventHandler(AddressOf mRecognizerContext_Recognition)

// 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_Stroke2);
// subscribe to the the Recognition event. 
// This event is fired when background recognition is complete, 
// and recognition results (without alternates) are available
mRecognizerContext.Recognition += 
    new RecognizerContextRecognitionEventHandler(mRecognizerContext_Recognition);

當 Stroke 事件引發時 (以回應完成筆劃的使用者)，剛建立的筆劃會加入至 RecognizerContext 物件的 Strokes 集合中，並且會呼叫 BackgroundRecognize 方法。

Private Sub mInkOverlay_Stroke2(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.BackgroundRecognize()
End Sub

private void mInkOverlay_Stroke2(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.BackgroundRecognize();
}

背景辨識完成時，會引發 Recognition 事件。在處理這個事件期間，辨識的結果會放置在清單方塊中。

' event fires when recognition results (without alternates) are ready
Private Sub mRecognizerContext_Recognition(ByVal sender As Object, _
            ByVal e As RecognizerContextRecognitionEventArgs)
    ' 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 RecognizerContextRecognitionEventHandler(AddressOf mRecognizerContext_Recognition), _
            New Object() {sender, e} _
        )
        Return
    End If
    If RecognitionStatus.NoError = e.RecognitionStatus Then
        listBoxRecognitionResults.Items.Add(e.Text)
    End If
End Sub

// event fires when recognition results (without alternates) are ready
private void mRecognizerContext_Recognition(object sender, RecognizerContextRecognitionEventArgs 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 RecognizerContextRecognitionEventHandler(mRecognizerContext_Recognition), 
            new object[] { sender, e }
            );
        return;
    }
    if (RecognitionStatus.NoError == e.RecognitionStatus)
    {
        listBoxRecognitionResults.Items.Add(e.Text);
    }
}