RawStylusInput.NotifyWhenProcessed(Object) Método

Definição

Namespace:

System.Windows.Input.StylusPlugIns

Assembly:

PresentationCore.dll

Assina os métodos de caneta correspondentes do thread do aplicativo.

public:
 void NotifyWhenProcessed(System::Object ^ callbackData);

public void NotifyWhenProcessed (object callbackData);

member this.NotifyWhenProcessed : obj -> unit

Public Sub NotifyWhenProcessed (callbackData As Object)

Parâmetros

callbackData

Object

Os dados a serem passados para o thread de aplicativo.

Exemplos

O exemplo a seguir cria um StylusPlugIn que verifica o Down gesto. As StylusPlugIn chamadas NotifyWhenProcessed OnStylusUp para assinar o OnStylusUpProcessed método, que é chamado do thread do aplicativo.

class RecognizerPlugin : StylusPlugIn
{
    GestureRecognizer recognizer;
    
    // StylusPointCollection that contains the stylus points of the current
    // stroke.
    StylusPointCollection points;

    // Keeps track of the stylus to check whether two styluses are used on the
    // digitizer.
    int currentStylus;

    public RecognizerPlugin()
        : base()
    {
        recognizer = new GestureRecognizer();
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusDown(RawStylusInput rawStylusInput)
    {
        // If points is not null, there is already a stroke taking place
        // on the digitizer, so don't create a new StylusPointsCollection.
        if (points == null)
        {
            points = new StylusPointCollection(rawStylusInput.GetStylusPoints().Description);
            points.Add(rawStylusInput.GetStylusPoints());
            currentStylus = rawStylusInput.StylusDeviceId;
        }
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusMove(RawStylusInput rawStylusInput)
    {
        // Check whether the stylus that started the stroke is the same, and
        // that the element hasn't lost focus since the stroke began.
            if (points != null && currentStylus == rawStylusInput.StylusDeviceId)
        {
            points.Add(rawStylusInput.GetStylusPoints());
        }
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusUp(RawStylusInput rawStylusInput)
    {
        // Check whether the stylus that started the stroke is the same, and
        // that the element hasn't lost focus since the stroke began.
        if (points != null && currentStylus == rawStylusInput.StylusDeviceId)
        {
            points.Add(rawStylusInput.GetStylusPoints());

            // Subscribe to the OnStylusUpProcessed method.
            rawStylusInput.NotifyWhenProcessed(points);
        }

        points = null;
        currentStylus = 0;
    }
        
    // If the element loses focus, stop collecting the points and don't
    // perform gesture recognition.
    protected override void OnStylusLeave(RawStylusInput rawStylusInput, bool confirmed)
    {
        if (confirmed)
        {
            // Clear the StylusPointCollection
            points = null;
            currentStylus = 0;
        }
    }

    // This method is called on the application thread.
    protected override void OnStylusUpProcessed(object callbackData, bool targetVerified)
    {
        // Check that the element actually receive the OnStylusUp input.
        if (targetVerified && recognizer.IsRecognizerAvailable)
        {
            StylusPointCollection strokePoints = callbackData as StylusPointCollection;

            if (strokePoints == null)
            {
                return;
            }

            // Create a StrokeCollection to pass to the GestureRecognizer.
            Stroke newStroke = new Stroke(strokePoints);
            StrokeCollection strokes = new StrokeCollection();
            strokes.Add(newStroke);

            ReadOnlyCollection<GestureRecognitionResult> results = recognizer.Recognize(strokes);

            // If the GestureRecognizer recognizes the stroke as a Down
            // gesture with strong confidence, raise an event.
            if (results[0].ApplicationGesture == ApplicationGesture.Down &&
                results[0].RecognitionConfidence == RecognitionConfidence.Strong)
            {
                //raise event
            }
        }
    }
}

Class RecognizerPlugin
    Inherits StylusPlugIn
    Private recognizer As GestureRecognizer

    ' StylusPointCollection that contains the stylus points of the current
    ' stroke.
    Private points As StylusPointCollection

    ' Keeps track of the stylus to check whether two styluses are used on the
    ' digitizer.
    Private currentStylus As Integer

    Public Sub New()
        recognizer = New GestureRecognizer()

    End Sub


    ' Collect the points as the user draws the stroke.
    Protected Overrides Sub OnStylusDown(ByVal rawStylusInput As RawStylusInput)

        ' If points is not null, there is already a stroke taking place
        ' on the digitizer, so don't create a new StylusPointsCollection.
        If points Is Nothing Then
            points = New StylusPointCollection(rawStylusInput.GetStylusPoints().Description)
            points.Add(rawStylusInput.GetStylusPoints())
            currentStylus = rawStylusInput.StylusDeviceId
        End If

    End Sub

    ' Collect the points as the user draws the stroke.
    Protected Overrides Sub OnStylusMove(ByVal rawStylusInput As RawStylusInput)

        ' Check whether the stylus that started the stroke is the same, and
        ' that the element hasn't lost focus since the stroke began.
        If Not (points Is Nothing) AndAlso currentStylus = rawStylusInput.StylusDeviceId Then
            points.Add(rawStylusInput.GetStylusPoints())
        End If

    End Sub

    ' Collect the points as the user draws the stroke.
    Protected Overrides Sub OnStylusUp(ByVal rawStylusInput As RawStylusInput)

        ' Check whether the stylus that started the stroke is the same, and
        ' that the element hasn't lost focus since the stroke began.
        If Not (points Is Nothing) AndAlso currentStylus = rawStylusInput.StylusDeviceId Then
            points.Add(rawStylusInput.GetStylusPoints())

            ' Subscribe to the OnStylusUpProcessed method.
            rawStylusInput.NotifyWhenProcessed(points)
        End If

        points = Nothing
        currentStylus = 0

    End Sub

    ' If the element loses focus, stop collecting the points and don't
    ' perform gesture recognition.
    Protected Overrides Sub OnStylusLeave(ByVal rawStylusInput As RawStylusInput, ByVal confirmed As Boolean)

        If confirmed Then
            ' Clear the StylusPointCollection
            points = Nothing
            currentStylus = 0
        End If

    End Sub

    ' This method is called on the application thread.
    Protected Overrides Sub OnStylusUpProcessed(ByVal callbackData As Object, ByVal targetVerified As Boolean)

        ' Check that the element actually receive the OnStylusUp input.
        If targetVerified AndAlso recognizer.IsRecognizerAvailable Then

            Dim strokePoints As StylusPointCollection = callbackData

            If strokePoints Is Nothing Then
                Return
            End If

            ' Create a StrokeCollection to pass to the GestureRecognizer.
            Dim newStroke As New Stroke(strokePoints)
            Dim strokes As New StrokeCollection()
            strokes.Add(newStroke)

            Dim results As ReadOnlyCollection(Of GestureRecognitionResult) = recognizer.Recognize(strokes)

            ' If the GestureRecognizer recognizes the stroke as a Down
            ' gesture with strong confidence, raise an event.
            If results(0).ApplicationGesture = ApplicationGesture.Down AndAlso _
               results(0).RecognitionConfidence = RecognitionConfidence.Strong Then
                'raise event
            End If
        End If

    End Sub
End Class

Comentários

A entrada da caneta é roteada para um elemento no thread de StylusPlugIn caneta. Como testes de acertos precisos não podem ser executados no thread da caneta, alguns elementos podem, ocasionalmente, receber entradas da caneta destinadas a outros elementos. Se você precisar ter certeza de que a entrada foi roteada corretamente antes de executar uma operação, chame o NotifyWhenProcessed método no método que ocorre no thread de caneta. A tabela a seguir lista onde chamar NotifyWhenProcessed para assinar o método do thread do aplicativo.

Chamar NotifyWhenProcessed neste método	Para assinar este método
OnStylusDown	OnStylusDownProcessed
OnStylusMove	OnStylusMoveProcessed
OnStylusUp	OnStylusUpProcessed