One or more BeginStoryboard object elements. Object elements defined here become members of the TriggerActionCollection that is the value of the Actions property, if you use code to examine that collection at run time.
You can manipulate the contents of the TriggerActionCollection, but you cannot replace it. You set the Actions value in XAML by placing one or more BeginStoryboard elements as the child elements of an EventTrigger object. You do not typically specify an EventTrigger.Actions property element, because Actions is the XAML content property of EventTrigger.