Here is Jesse Liberty's next part from the series 'Windows Phone From Scratch'.
Source: Jesse Liberty's Blog
In previous postings, I’ve discussed the Life Cycle of a Windows Phone application and in that context noted the requirement to maintain the page’s state when the user navigates away (so that state can be restored when the user returns)
There are a few practical elements to state management, so let’s devote a few of these mini-tutorials to the exact mechanisms involved.