# EVENT_MARK_STATE_CHANGE

Object Types: Trees and list boxes.

Description: Mark state change events are sent to the callback function when the check state changes for a list box item or tree item.

Event Data Parameters:

eventData1 | = | The new mark state of the list item.
eventData2 | = | itemIndex of the item whose mark state is being changed.

This event is swallowable. Return 1 to swallow EVENT_MARK_STATE_CHANGE.

For list box controls, this event is swallowable if you set ATTR_DRAGGABLE_MARKS to on. This event is not swallowable if you set ATTR_DRAGGABLE_MARKS to off.

For tree controls, any mark state event that is generated as a result of a mark reflect change is not swallowable.

For tree items with radio buttons, the event that is swallowable is the event that is generated when you select an item. If, when you select an item, another item becomes deselected as a result, then that event is not swallowable.