Mouse Event Promotion

With the advent of Windows Phone, Silverlight transitioned from being a browser and desktop-only technology with a primarily mouse-driven UI, to a mobile device technology with a touch-driven UI.

To allow controls that were originally designed to work with mouse events to continue to function, the touch system was engineered so that touch events are automatically turned into (promoted to) mouse events. If a touch event is not suspended using the SuspendMousePromotionUntilTouchUp method, then mouse events are automatically raised.

To prevent a touch event from being promoted to a mouse event, call the SuspendMousePromotionUntilTouchUp within the FrameReported event handler, like so:

Click here to view code image

void HandleFrameReported(object sender, TouchFrameEventArgs e)
{
    TouchPoint primaryTouchPoint = e.GetPrimaryTouchPoint(null);
    if (primaryTouchPoint != null
        && primaryTouchPoint.Action == TouchAction.Down)
    {
        e.SuspendMousePromotionUntilTouchUp();
        /* custom code */
    }
}

In most cases, calling SuspendMousePromotionUntilTouchUp is something you should avoid, because doing so prevents the functioning of any controls that rely solely on mouse events and those that have not been built using the touch-specific API.