WPF简单易懂的使用定时器更新UI界面

使用定时器制作一个显示时间的效果，如下所示：

UI布局如下所示：

<Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <TextBlock x:Name="txt" FontSize="100" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <StackPanel
            Grid.Row="1"
            HorizontalAlignment="Center"
            Orientation="Horizontal">
            <Button
                x:Name="start"
                Width="120"
                Height="30"
                Margin="10"
                Content="开始" Click="Button_Click" />
            <Button
                x:Name="stop"
                Width="120"
                Height="30"
                Margin="10"
                Content="暂停"
                IsEnabled="False" Click="btn_Click"/>
        </StackPanel>
</Grid>

后台代码如下所示：

using System;
using System.Windows;
using System.Windows.Threading;

namespace TheadPoolDemo
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            dispatcherTimer = new DispatcherTimer();
            dispatcherTimer.Interval = TimeSpan.FromMilliseconds(100);  // 100ms 更新一次
            dispatcherTimer.Tick += DispatcherTimer_Tick;
        }

        DispatcherTimer dispatcherTimer = null;

        private void DispatcherTimer_Tick(object sender, EventArgs e)
        {
            this.txt.Text = DateTime.Now.ToString("HH:mm:ss");
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            dispatcherTimer.Start();
            this.start.IsEnabled = false;
            this.stop.IsEnabled = true;
        }

        private void btn_Click(object sender, RoutedEventArgs e)
        {
            dispatcherTimer.Stop();
            this.stop.IsEnabled = false;
            this.start.IsEnabled = true;
        }
    }
}