The event is cancelable
cancel returns whether the event has been interepted and stopped
If the value becomes "true", it returns/exits from the method, instanciating the interface
Optional eventOptional Represents the original event, that has triggered the expantion/collapse
Returns the state of the row after the operation has ended Indicating whether the row is being expanded (true) or collapsed (false)
Optional ownerProvides reference to the owner component.
Represents the ID of the row that emitted the event (which state is changed)
since version 17.1.0. Use the rowKey property instead.
Рepresents event arguments related to the row's expansion state being changed in a grid