WP7 Loading animation for content

I tried to find an example for content loading animation (to learn how to implement one in my app). But I couldn't find one.

What I want is: There are 4 listboxes in my mainpage and I want to show a loading animation until the listboxes have completed loading their data.

For example,IMDB application has a lo开发者_C百科ading animation like I want. (You can watch it here http://www.youtube.com/watch?v=AV9BoyGm7Fo)

Any ideas on how to create this?

Thanks

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Please refer to these links, as they seem to provide the exact solution to coding this standard loading animation:

Creating a Splash Screen with a progress bar for WP7 applications

High Performance ProgressBar for Windows Phone 7