UIElement.PointerMoved event

Occurs when a pointer moves while the pointer remains within the hit test area of this element.

Syntax

public event PointerEventHandler PointerMoved

<uiElement PointerMoved="eventhandler"/>

Event information

Remarks

Touch, mouse, and pen/stylus interactions are received, processed, and managed as pointer input in Windows Store apps. Any of these interactions can produce a PointerMoved event. For more info, see Quickstart: Pointers and the "PointerMoved for mouse and stylus input" section of this topic.

In some UI scenarios, particularly if the user is using a mouse, this event will fire a lot. Be aware of the performance profile for code you put into this handler, and consider ways to use your own flags or tolerances that can throttle how many times the logic actually needs to run.

This event is a routed event. For more info on the routed event concept, see Events and routed events overview.

For touch actions and also for interaction-specific or manipulation events that are consequences of a touch action, an element must be hit-test visible in order to be the event source and fire the event that is associated with the action. UIElement.Visibility must be Visible. Other properties of derived types also affect hit-test visibility. For more info, see Hit testing and input events.

This event also supports the ability to attach event handlers to the route that will be invoked even if the event data for the event is marked Handled. See AddHandler.

PointerMoved for mouse and stylus input

A mouse input device has an onscreen cursor that is visible whenever the mouse moves over an element's bounds, even if no mouse button is pressed at the time. Similar behavior is available for pen device input, where the input devices can detect that the pen is hovering just over the input device surface but not touching it. Mouse and pen input will thus fire PointerMoved events more often than touch input. For more info, see Responding to mouse interactions.

In contrast, a touch point is only detectable if a finger is touching the surface. A touch point will generate PointerMoved only while that touch point remains in constant contact with the surface as it moves. For these kinds of touch actions that are generating PointerMoved it's also likely that the action will be processed as a manipulation, or as a gesture. For more info, see Quickstart: Touch input.

Mouse input is associated with a single pointer assigned when mouse input is first detected, and all mouse-initiated interactions have the same PointerId. Clicking a mouse button (left, wheel, or right) creates a secondary association between the pointer and that button through the PointerPressed event. The PointerReleased event is fired only when that same mouse button is released (no other button can be associated with the pointer until this event is complete). Because of this exclusive association, other mouse button clicks are routed through the PointerMoved event. You can test the mouse button state when handling this event, as shown in this example:

private void Target_PointerMoved(object sender, PointerRoutedEventArgs e)
{
    Windows.UI.Xaml.Input.Pointer ptr = e.Pointer;

    // Multiple, simultaneous mouse button inputs are processed here.
    // Mouse input is associated with a single pointer assigned when 
    // mouse input is first detected. 
    // Clicking additional mouse buttons (left, wheel, or right) during 
    // the interaction creates secondary associations between those buttons 
    // and the pointer through the pointer pressed event. 
    // The pointer released event is fired only when the last mouse button 
    // associated with the interaction (not necessarily the initial button) 
    // is released. 
    // Because of this exclusive association, other mouse button clicks are 
    // routed through the pointer move event.          
    if (ptr.PointerDeviceType == Windows.Devices.Input.PointerDeviceType.Mouse)
    {
        // To get mouse state, we need extended pointer details.
        // We get the pointer info through the getCurrentPoint method
        // of the event argument. 
        Windows.UI.Input.PointerPoint ptrPt = e.GetCurrentPoint(Target);
        if (ptrPt.Properties.IsLeftButtonPressed)
        {
            eventLog.Text += "\nLeft button: " + ptrPt.PointerId;
        }
        if (ptrPt.Properties.IsMiddleButtonPressed)
        {
            eventLog.Text += "\nWheel button: " + ptrPt.PointerId;
        }
        if (ptrPt.Properties.IsRightButtonPressed)
        {
            eventLog.Text += "\nRight button: " + ptrPt.PointerId;
        }
    }

    // Prevent most handlers along the event route from handling the same event again.
    e.Handled = true;

    // Display pointer details.
    updateInfoPop(e);
}

Requirements

See also

UIElement

PointerEntered

OnPointerMoved

Quickstart: Touch input

Quickstart: Handling pointer input

XAML user input events sample

Build date: 1/31/2013