<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 Name="gd_Model">
        <Label Content="{Binding NumberFirst}" Margin="0,0,211,218"></Label>
        <Label Content="{Binding NumberSecond}" Margin="0,99,211,107"></Label>
        <Button Width="80" Height="30" Click="btn_Click" Margin="365,158,58,124"></Button>
    </Grid>
</Window>

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.ComponentModel;

namespace WpfApplication1
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        PlusModel model_PlusModel = new PlusModel();
        public MainWindow()
        {
            InitializeComponent();
            model_PlusModel.NumberFirst = 5;
            model_PlusModel.NumberSecond = 5;
            gd_Model.DataContext = model_PlusModel;
        }
        public void btn_Click(object sender, RoutedEventArgs e)
        {
            model_PlusModel.NumberFirst++;
            model_PlusModel.NumberSecond++;
        }
       
    }
    public class PlusModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public PlusModel()
        {

        }
        /// <summary>
        /// 第一个加数
        /// </summary>
        private decimal _numberFirst;
        /// <summary>
        /// 第二个加数
        /// </summary>
        private decimal _numberSecond;
      
        /// <summary>
        /// 第一个加数
        /// </summary>
        public decimal NumberFirst
        {
            get
            {
                return _numberFirst;
            }
            set
            {
                _numberFirst = value;
                if (PropertyChanged != null)
                {                   
                    PropertyChanged(this, new PropertyChangedEventArgs("NumberFirst"));                    
                }
            }
        }
        /// <summary>
        /// 第二个加数
        /// </summary>
        public decimal NumberSecond
        {
            get
            {
                return _numberSecond;
            }
            set
            {
                _numberSecond = value;               
            }
        }
        
    }
}