WPF 使用定时器

WPF 使用定时器：
<ProgressBar Height="10" HorizontalAlignment="Left" Margin="288,0,0,189" Name="progressBar1"

VerticalAlignment="Bottom" Width="100" />
后台：
 private void button1_Click(object sender, RoutedEventArgs e)
        {
            Window_Loaded2();
            
           
        }
        private void Window_Loaded2()
        {
            DispatcherTimer _mainTimer = new DispatcherTimer();
            _mainTimer.Interval = TimeSpan.FromSeconds(1);
            _mainTimer.Tick += new EventHandler(_mainTimer_Tick);
            _mainTimer.IsEnabled = true;
            //Timer tmr = new Timer();
            //tmr.Interval = 100;
            //tmr.Enabled = true;
            //tmr.Tick += new EventHandler(tmr_Tick);
            
        }
        void _mainTimer_Tick(object sender, EventArgs e)
        {
            if (progressBar1.Value == progressBar1.Maximum)
                progressBar1.Value = 0;

            progressBar1.Value++;
        }
private void tmr_Tick(object sender, EventArgs e)
        {
            if (progressBar1.Value == progressBar1.Maximum) progressBar1.Value = 0;

            progressBar1.Value++;
        }