There are a number of different types of Triggers that you can use. In your example, you are using a Data Trigger. For Event, you need to use an EventTrigger.
I wrote an WPF article earlier this month about a ToggleSwitch control. In it I share an example of replicating the Notification Settings screen from Windows 10. In the article XAML code snippet I show how to use the EventTrigger for MouseOver. This is an ideal example for you: Flexible WPF ToggleSwitch Lookless Control in C# & VB
] - download the code and you can see how it works.