Add event to a WPF custom control library in Windows Form

[C# Programming]

Hi
I'm currently working on a project using C# Windows Forms. I need to add some animation on the form and I found WPF can do animation very easily. I'm very new to WPF. I searched on google and found some tutorial. Now I can add a WPF user control library to a windows form and the animation works fine but I need to control the animation, eg. When the user control library got focus, the animation starts? How can I do this??

Help please!

Thanks