using (IsolatedStorageFile storeForApplication = IsolatedStorageFile.GetUserStoreForApplication())
      {
        using (IsolatedStorageFileStream storageFileStream = new IsolatedStorageFileStream(str, FileMode.Create, storeForApplication))
        {
          using (StreamWriter streamWriter = new StreamWriter((Stream) storageFileStream))
            streamWriter.WriteLine("[...] and the number of the counting shall be three.");
        }
        storeForApplication.DeleteFile(str);
      }