July 28, 2014For apps that target Windows Phone OS 7.0 and 7.1, do not use this member in your app. If you do, your code will throw a MethodAccessException. This member is security-critical, which restricts it to internal use by the .NET Framework for Windows Phone class library.
[SECURITY CRITICAL]Namespace: System.IO
Sets the application's current working directory to the specified directory.
Assembly: mscorlib (in mscorlib.dll)