Storyboard.TargetName Attached Property
Gets or sets the name of the object to animate.
Assembly: System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.
Dependency property identifier field: TargetNameProperty
The value of must refer to an existing element that has that same string assigned as its Name or x:Name attribute. For details, see the "Creating a Storyboard" section of Animations, motion, and output for Windows Phone.
Attempting to set on a running animation will cause a run-time error. However, you can retarget an existing animation is stopped or not yet running. If you do so, be careful not to retarget an animation to the wrong type of target (one that does not possess the existing Storyboard.TargetProperty). Otherwise, you will get a run-time error.