Animation and Visual State
One of the things that sharply distinguish XAML from simpler markup languages such as HTML is that XAML supports declarative animation. That is, you can indicate a property and the change you’d like to have happen to that property over a set amount of time. For example, you might indicate that the height of an object show grow from 45 to 90 pixels over 1 second.
XAML animation is managed by
Storyboard is a named set of XAML declarations that detail the steps of an animation. A
Storyboard has a key so that you can refer to it programmatically, and it has within it XAML objects called animations. ...