Animation during User-control change in wpf

I am looking for this:

Say For example, I have 2 user-controls: uc1.xaml and uc2.xaml and 1 mainwindow in my application. Now, when the application opens mainwindow will show 1st usercontrol i.e uc1. Hence, how to animate to slide effect or any other effect while mainwindow shows uc1. Also, when I click button on uc1, mainwindow switch from uc1 to uc2. I also need to have animation at this step. Kindly help me with some sample code.

Kindly help!!

Note: I am using wpf desktop application and it is "NOT" winforms application.

Thank you very much in advance.