With Windows Phone 8, now you can use two ways to work with files and directories in Windows Phone. The first is the .NET Isolated Storage API, and the second is the WinPRT Windows Storage API. The .NET Isolated Storage API is still fully supported and provides cross-platform compatibility with Silverlight. It also provides built-in support for application settings, which the WinPRT Windows Storage API does not. The WinPRT Windows Storage API is new to Windows Phone 8 and provides cross-platform compatibility with the Windows 8 WinRT Windows Storage API.
This section touches on both approaches, beginning with the .NET Isolated Storage API.