TouchFrameEventArgs Class

 

Provides data for the Touch.FrameReported event.

Namespace:   System.Windows.Input
Assembly:  PresentationCore (in PresentationCore.dll)

System.Object
  System.EventArgs
    System.Windows.Input.TouchFrameEventArgs

Public NotInheritable Class TouchFrameEventArgs
	Inherits EventArgs

NameDescription
System_CAPS_pubpropertyTimestamp

Gets the time stamp for this event.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetPrimaryTouchPoint(IInputElement)

Returns the current touch point of the primary touch device relative to the specified element.

System_CAPS_pubmethodGetTouchPoints(IInputElement)

Returns a collection that contains the current touch point for each active touch device relative to the specified element.

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodSuspendMousePromotionUntilTouchUp()

This member is not implemented.

System_CAPS_pubmethodToString()

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

The FrameReported event is included in Windows Presentation Foundation (WPF) to support compatibility with Silverlight. If you do not have to ensure compatibility with Silverlight, use the touch events, such as TouchDown and TouchMove, on UIElement, UIElement3D, or ContentElement.

Use the TouchFrameEventArgs to get the TouchPoint values that are relevant to the touch event. From the TouchPoint, you can get the Position of the touch and determine whether the TouchAction was a Down, Move, or Up action. You can also use the TouchPoint to get the TouchDevice. From the TouchDevice, you can determine the device Id and get information about the element that is touched.

The following example handles the FrameReported event and accesses the touch data in the TouchFrameEventArgs. When a touch is pressed on the Canvas, the TouchDevice is captured to the Canvas. When the touch is lifted, the TouchDevice is released. When a touch moves across the Canvas, the Id is checked. If the move came from the first touch, its location is recorded. If the move came from the second touch, a line is drawn from the position of the first touch to the position of the second touch.

This example is part of a larger example that is available in the Touch class overview.

Class MainWindow
    ' Variables for tracking the position of two points.
    Private pt1, pt2 As Point

    Public Sub New()
        InitializeComponent()
        AddHandler Touch.FrameReported, AddressOf Touch_FrameReported
    End Sub

    Private Sub Touch_FrameReported(ByVal sender As System.Object, ByVal e As System.Windows.Input.TouchFrameEventArgs)
        If (canvas1 IsNot Nothing) Then
            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
        End If
    End Sub
End Class

.NET Framework
Available since 4.0
Silverlight
Available since 3.0
Windows Phone Silverlight
Available since 7.0

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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