Windows Phone 8 and Isolated Storage (Settings , Files and folders)

using System.IO.IsolatedStorage;


namespace myPhoneApp
{

    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }


        private void btnSave_Click(object sender, RoutedEventArgs e)
        {
            IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;
            // txtInput is a TextBox defined in XAML.
            if (!settings.Contains("userData"))
            {
                settings.Add("userData", txtInput.Text);
            }
            else
            {
                settings["userData"] = txtInput.Text;
            }
            settings.Save();
        }


        private void btnDisplay_Click(object sender, RoutedEventArgs e)
        {
            // txtDisplay is a TextBlock defined in XAML.
            txtDisplay.Text = "USER DATA: ";
            if (IsolatedStorageSettings.ApplicationSettings.Contains("userData"))
            {
                txtDisplay.Text +=
                IsolatedStorageSettings.ApplicationSettings["userData"] as string;
            }
        }

        private void btnRemove_Click(object sender, RoutedEventArgs e)
        {
            if (IsolatedStorageSettings.ApplicationSettings.Contains("userData"))
            {
                IsolatedStorageSettings.ApplicationSettings.Remove("userData");
            }
        }

    }
}

using System.IO.IsolatedStorage;

            private string strFileName = "thaicreate.txt";

            // Create Isolated StorageFile
            IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication();

            // Create File Name
            if (!isoStore.FileExists(strFileName))
            {
                IsolatedStorageFileStream dataFile = isoStore.CreateFile(strFileName);
            }

            // Write text file
            StreamWriter sw = new StreamWriter(new IsolatedStorageFileStream(strFileName, FileMode.Append, isoStore));
            sw.WriteLine(this.textBox1.Text);
            sw.Close();

            private string strFileName = "thaicreate.txt";

            // Create Isolated StorageFile
            IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication();

            // Read text file
            StreamReader reader = new StreamReader(new IsolatedStorageFileStream(strFileName, FileMode.Open, isoStore));
            string rawData = reader.ReadToEnd();
            reader.Close();

        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0">
            <TextBox 
                Name="textBox1" 
                HorizontalAlignment="Left"
                Height="72" 
                Margin="0,22,0,0" 
                TextWrapping="Wrap" 
                Text="Enter text here." 
                VerticalAlignment="Top" Width="456"/>
            <Button 
                Name='btnWrite' 
                Content="Write"
                HorizontalAlignment="Left" 
                Margin="10,94,0,0" 
                VerticalAlignment="Top"
                Width="156" 
                Click="btnWrite_Click"/>
            <TextBlock 
                Name="textBlock1" 
                HorizontalAlignment="Left"
                Margin="10,293,0,0" 
                TextWrapping="Wrap" Text=""
                VerticalAlignment="Top" 
                Height="61" 
                Width="436"/>
            <Button 
                Name="btnRead" 
                Content="Read"
                HorizontalAlignment="Left" 
                Margin="10,374,0,0" 
                VerticalAlignment="Top"
                Width="156" 
                IsEnabled="False"
                Click="btnRead_Click"/>
        </Grid>