Flash: how can I cast a slider class to DisplayObject in Flash?

I tried this:

    (DisplayObject(slider)).parent.addEventListener(CustomEvent.CUSTOM_EVENT_TYPE, onCustomEventType);

but开发者_运维问答 flash doesn't like

For whole context see Is it impossible with Flash to get the Instance Creator?

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(slider as DisplayObject).parent.addEventListener(CustomEvent.CUSTOM_EVENT_TYPE, onCustomEventType);