public partial class MainPage : PhoneApplicationPage
    {
        int num = 0;

        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            Thread th1 = new Thread(new ThreadStart(GetNum));
            Thread th2 = new Thread(new ThreadStart(GetNum));

            th1.Start();
            th2.Start();

            textBlock1.Text = num.ToString();
        }

        private void GetNum()
        {
            for (int i = 0; i < 50; i++)
            {
                num++;
            }
        }
    }