1.前台代码

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525"
        >
    <Grid>
        <ProgressBar Height="20" Name="ProgressBar1" Value="60" Width="200" Foreground="Blue" Background="Red" />
        <Button Content="Button" Height="30" HorizontalAlignment="Left" Margin="192,240,0,0" Name="button1" VerticalAlignment="Top" Width="124" Click="button1_Click" />
    </Grid>
</Window>

2.后台代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Threading;
using System.Threading;

namespace WpfApplication1
{

/// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

private void button1_Click(object sender, RoutedEventArgs e)
        {
            ProgressBar1.Value -= 10;
        }
    }
}