Pro Silverlight 4 in C#

Chapter 18. File Access

Silverlight includes a surprisingly capable set of features for saving, reading, and managing files. The key fact you need to understand is that ordinary Silverlight applications aren't allowed to write to (or read from) arbitrary locations on the file system. Instead, Silverlight applications that need to store data permanently must use a feature called isolated storage.

Isolated storage gives you access to a small segment of hard-disk space, with certain limitations. For instance, you don't know exactly where your files are being stored. You also can't read the files left by another Silverlight application or recorded for another user. In essence, isolated storage provides carefully restricted, tamperproof file access ...