using System;using System.Windows;using System.Timers;using System.Windows.Threading;namespace TimerTest{/// 
/// Interaction logic for MainWindow.xaml/// 
    public partial class MainWindow : Window    {        private Timer aTimer = null;        private delegate void TimerDispatcherDelegate();        public MainWindow()        {            InitializeComponent();            aTimer = new Timer(1000);            aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);            aTimer.Interval = 1000;            aTimer.Enabled = true;        }        private void OnTimedEvent(object sender, EventArgs e)        {            this.Dispatcher.Invoke(DispatcherPriority.Normal,                new TimerDispatcherDelegate(updateUI));        }        private void updateUI()        {            timeLabel.Content = DateTime.Now.ToUniversalTime();        }    }}

http://www.cnblogs.com/zhchbin/archive/2012/03/06/2381693.html