InteractiveService Object


Defines the service to translate mouse and touch events to common user interface interactions.

function lt.Controls.InteractiveService 
	implements IDisposable 
class lt.Controls.InteractiveService() 
	implements IDisposable 

The InteractiveService object hooks to any element events and can be used to provide uniform tap, move, drag, hold, double tap, drag and pinch events. This can be done regardless of whether the platform supports mouse or touch events.

(A separate functionality, User-Defined HTML Display, allows for native pointer events on HTML or SVG Elements that have been added to Element in Elements Mode when HTML Pointer Events is supported.)

ImageViewer contains an instance of InteractiveService internally (accessible through the ImageViewer.InteractiveService property) and use it along with the ImageViewerInteractiveMode classes to perform rich interactive user interface interactions such as zoom, pan, scale, rubber banding and magnify glass.

To use the InteractiveService, call the Create method passing an HTML element that will act as the events source (EventsSource). The events of this element will be subscribed to and converted from raw mouse and touch to the common events mentioned above. Also, the Create method takes another HTML element that will act as the events target (EventsTarget). This element is the target that will be used to check if the event is triggered on its surface. All coordinates will be translated based on its position. In the case of ImageViewer, the main element (ImageViewer.MainDiv) will act as the events source and the foreground element (ImageViewer.ForeCanvas) will act as the events target. This insures that all events inside the viewer surface will act upon and be translated into the foreground element coordinates.

InteractiveService contains the following members:

Members Description


The owner of the service. This is not used by InteractiveService but can be used by the application to pass any class and extra data. ImageViewer passes this for this parameter in the Create method.


The events source element.


The events target element.


Any extra elements that should participate in the events handling.

HitTestBuffer, PreventContextMenu, TapOnDown, DragStartsOnDown, PinchStartsOnDown, EnableMouseWheel and EnableSelection

Options used to modify the operations of the service.

StartListening, StopListening and IsListening

Subscribe/Unsubscribe to the events

Tap, DoubleTap, Move, Hold, DragStarted, DragDelta, DragCompleted, PinchStarted, PinchDelta and PinchCompleted

Uniform events for common user interface interaction regardless of the event source (mouse or touch)

KeyDown and KeyUp.

Keyboard events

InteractiveService will subscribe to multiple native events. It is recommended if you create an instance of this object to call Dispose on it when you are done to free the resources used. ImageViewer will dispose its instance of InteractiveService when ImageViewer.Dispose is called.


Target Platforms

Help Version 22.0.2021.9.24
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Leadtools.Controls Assembly
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© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.