Occurs when a touch message is sent.
Assembly: PresentationCore (in PresentationCore.dll)
A frame is one in a series of multitouch messages or touch points. You can respond to touches by handling the event and accessing the details of the TouchPoint from the TouchFrameEventArgs event data.
The event does not use the same event model as other WPF input events, such as TouchDown and TouchMove. Instead of being exposed as an element-specific event that potentially routes through the object tree of a UI, the event is a single event that is handled at the application level. Therefore, you cannot use the sender parameter of the event handler to determine what element is touched.
The following example handles the event. When a touch presses 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
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.