Windows Phone 7 Help

private void btnWrite_Click(object sender, RoutedEventArgs e)
        {
       // Get the local folder.
    System.IO.IsolatedStorage.IsolatedStorageFile local =
        System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication();

            

    // Create a new folder named DataFolder.
    if (!local.DirectoryExists("DataFolder"))
        local.CreateDirectory("DataFolder");

    // Create a new file named DataFile.txt.
    using (var isoFileStream = 
            new System.IO.IsolatedStorage.IsolatedStorageFileStream(
                "DataFolder\\DataFile.txt", 
                System.IO.FileMode.OpenOrCreate,
                    local))
    {
        // Write the data from the textbox.
        using (var isoFileWriter = new System.IO.StreamWriter(isoFileStream))
        {
            isoFileWriter.WriteLine(this.textBox1.Text);
        }
    }

    // Update UI.
    this.btnWrite.IsEnabled = false;
    this.btnRead.IsEnabled = true;
}

            private void btnRead_Click(object sender, RoutedEventArgs e)
{
  
   // Obtain a virtual store for the application.
    System.IO.IsolatedStorage.IsolatedStorageFile local =
        System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication();

    // Specify the file path and options.
    using (var isoFileStream =
            new System.IO.IsolatedStorage.IsolatedStorageFileStream
                ("DataFolder\\DataFile.txt", System.IO.FileMode.Open, local))
    {
        // Read the data.
        using (var isoFileReader = new System.IO.StreamReader(isoFileStream))
        {
            this.textBlock1.Text = isoFileReader.ReadLine();
        }
    }
    // Update UI.
    this.btnWrite.IsEnabled = true;
    this.btnRead.IsEnabled = false;
  

  
}