Is it possible to capture the contents of running Windows store app? I need to capture the entire screen or a user defined rectangular area.
It's now possible in Windows 8.1 to capture the screen of a Store App. You need to use the RenderTargetBitmap class.
You can find an example here: http://mariusbancila.ro/blog/2013/11/05/render-the-screen-of-a-windows-store-app-to-a-bitmap-in-windows-8-1/
Hope it helps.