windows phone 8 - Deleting local database sdf file from isolated storage -

i trying delete local database file 'transferdb.sdf' via code.

    pridedatacontext db = new pridedatacontext(app.dbconnectionstring);                  if (db.databaseexists())                 {                     //db.dispose();                    db.deletedatabase();                 } 

but when try run code gives me following exception.

$exception {system.io.ioexception: process cannot access file 'c:\data\users\defapps\appdata{af715f29-8bfc-48de-ad88-e71d8f37bc26}\local\transferdb.sdf' because being used process.

why is trying delete file in local data folder instead of in real device testing?

pretty confused. can me here? ( think referring 1 of emulator's temporary sdf file instead of device's one)