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The OnClientDragging client-side event occurs each time the user moves a mouse while dragging an item. This event can be cancelled.

The event handler receives two parameters:

  1. The instance of the listbox firing the event

  2. An event arguments parameter containing the following methods:

  • get_sourceItem() - returns the first selected item that is dragged

  • get_sourceItems() - returns an array of the selected items that are dragged

  • set_cancel() - lets you cancel the event and prevent the dragging.

  • get_domEvent() - returns the DOM event object

  • get_htmlElement() - returns the DOM html element which the item is dropped onto.

The example below demonstrates getting the current x and y coordinates of the mouse while the item is being dragged.

function OnClientDraggingHandler(sender, eventArgs) {
    var domEvent = eventArgs.get_domEvent();    
    var item = eventArgs.get_sourceItem();
    item.set_text("Dragging X:" + domEvent.offsetX + " Y:" + domEvent.offsetY);
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