$dragMark

called during drag-n-drop, when some item of the component should be marked as an active drop target

boolean $dragMark(object context,Event ev);

context	object	a drag-n-drop context
ev	Event	a native HTML event

boolean

returning false will prevent a drag operation

Related samples

DataTable. Custom Drag-and-Drop Behavior

Details

The method isn't purposed for direct call! It is an extension point.

You can override it with your own logic, but check drag-n-drop related events first, as they provide a much more convenient way of drag-n-drop handling.

The drag-and-drop context can have the following properties:

from - the source object
to - the target object
source - the id of dragged item(s)
target - the id of the drop target, null for a drop on an empty space
start - the id from which drag-and-drop has started