How can I cancel a DataGrid ToolTip before its shown?

I've got a DataGrid that shows a tooltip on each item.. but there are a few items where there shouldn't be a tooltip. So I thought I could prevent the being showed.

protected function toolTipStart(event:ToolTipEvent) : void
{
  LOG.debug('Start  ' + event); 

  event.stopImm开发者_如何学编程ediatePropagation();
}

But it does not work. Has anyone an idea?

regards Cyrill

stopImmedatePropogation will just stop further event listeners from catching the event; it does not have a relation to whether or not the toolTip is created.

I'm pretty sure you set the toolTip property of the event to null; then the toolTip will not show up.