TouchFrameEventArgs.GetTouchPoints(IInputElement) Metodo

Definizione

Spazio dei nomi:

System.Windows.Input

Assembly:

PresentationCore.dll

Restituisce un insieme che contiene il punto di tocco corrente per ogni dispositivo a tocco attivo relativo all'elemento specificato.

public:
 System::Windows::Input::TouchPointCollection ^ GetTouchPoints(System::Windows::IInputElement ^ relativeTo);

public System.Windows.Input.TouchPointCollection GetTouchPoints (System.Windows.IInputElement relativeTo);

member this.GetTouchPoints : System.Windows.IInputElement -> System.Windows.Input.TouchPointCollection

Public Function GetTouchPoints (relativeTo As IInputElement) As TouchPointCollection

Parametri

relativeTo

IInputElement

Elemento che definisce lo spazio delle coordinate. Per utilizzare le coordinate assolute WPF, specificare relativeTo come null.

Restituisce

TouchPointCollection

Insieme contenente l'oggetto TouchPoint corrente per ogni oggetto TouchDevice attivo.

Esempio

Il codice seguente elabora i punti di tocco recuperati dall'oggetto TouchFrameEventArgs. Quando un tocco viene premuto sull'area di disegno, viene TouchDevice acquisito nell'area di disegno. Quando viene generato il tocco, viene rilasciato.TouchDevice Quando un tocco si sposta nell'area di disegno, viene Id controllato. Se corrisponde Id all'oggetto Id del punto di tocco primario, che indica il primo tocco, viene registrata la sua posizione. Se lo spostamento proviene dal secondo tocco, una linea viene disegnata dalla posizione del primo tocco alla posizione del secondo tocco.

Questo esempio fa parte di un esempio più grande disponibile nella panoramica della Touch classe.

foreach (TouchPoint _touchPoint in e.GetTouchPoints(this.canvas1))
{
    if (_touchPoint.Action == TouchAction.Down)
    {
        // Clear the canvas and capture the touch to it.
        this.canvas1.Children.Clear();
        _touchPoint.TouchDevice.Capture(this.canvas1);
    }

    else if (_touchPoint.Action == TouchAction.Move && e.GetPrimaryTouchPoint(this.canvas1) != null)
    {   
        // This is the first (primary) touch point. Just record its position.
        if (_touchPoint.TouchDevice.Id == e.GetPrimaryTouchPoint(this.canvas1).TouchDevice.Id)
        {
            pt1.X = _touchPoint.Position.X;
            pt1.Y = _touchPoint.Position.Y;
        }

        // This is not the first touch point. Draw a line from the first point to this one.
        else if (_touchPoint.TouchDevice.Id != e.GetPrimaryTouchPoint(this.canvas1).TouchDevice.Id)
        {
            pt2.X = _touchPoint.Position.X;
            pt2.Y = _touchPoint.Position.Y;

            Line _line = new Line();
            _line.Stroke = new RadialGradientBrush(Colors.White, Colors.Black);
            _line.X1 = pt1.X;
            _line.X2 = pt2.X;
            _line.Y1 = pt1.Y;
            _line.Y2 = pt2.Y;
            _line.StrokeThickness = 2;
            this.canvas1.Children.Add(_line);
        }
    }

    else if (_touchPoint.Action == TouchAction.Up)
    {
        // If this touch is captured to the canvas, release it.
        if (_touchPoint.TouchDevice.Captured == this.canvas1)
        {
            this.canvas1.ReleaseTouchCapture(_touchPoint.TouchDevice);
        }
    }
}

For Each _touchPoint In e.GetTouchPoints(Me.canvas1)

    If _touchPoint.Action = TouchAction.Down Then
        ' Clear the canvas and capture the touch to it.
        canvas1.Children.Clear()
        _touchPoint.TouchDevice.Capture(canvas1)

    ElseIf _touchPoint.Action = TouchAction.Move Then
        ' This is the first (primary) touch point. Just record its position.
        If _touchPoint.TouchDevice.Id = e.GetPrimaryTouchPoint(Me.canvas1).TouchDevice.Id Then
            pt1.X = _touchPoint.Position.X
            pt1.Y = _touchPoint.Position.Y

            ' This is not the first touch point; draw a line from the first point to this one.
        ElseIf _touchPoint.TouchDevice.Id <> e.GetPrimaryTouchPoint(Me.canvas1).TouchDevice.Id Then
            pt2.X = _touchPoint.Position.X
            pt2.Y = _touchPoint.Position.Y

            Dim _line As New Line()
            _line.Stroke = New RadialGradientBrush(Colors.White, Colors.Black)
            _line.X1 = pt1.X
            _line.X2 = pt2.X
            _line.Y1 = pt1.Y
            _line.Y2 = pt2.Y

            _line.StrokeThickness = 2
            Me.canvas1.Children.Add(_line)
        End If

    ElseIf _touchPoint.Action = TouchAction.Up Then
        ' If this touch is captured to the canvas, release it.
        If (_touchPoint.TouchDevice.Captured Is canvas1) Then
            canvas1.ReleaseTouchCapture(_touchPoint.TouchDevice)
        End If
    End If
Next