wpf 数据绑定 联系

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.ComponentModel;

变量：
namespace 联系
{

     public class DA:INotifyPropertyChanged
    {
         private string _Name;

        public string Name
        {
            get { return _Name; }
            set { _Name = value;
            OnPropertyChanged("Name");
            }
         
        }
        private string _Pwd;

    
    public string Pwd
        {
            get { return _Pwd; }
            set
            {
                _Pwd = value; OnPropertyChanged("Pwd");

            }
        }

        public event PropertyChangedEventHandler PropertyChanged;//
        public virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

表里添加：
<Window x:Class="联系.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="300" Width="300">
    <Grid>
        <Label Content="显示" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="19,26,0,0"/>
        <TextBox Name="aaa" HorizontalAlignment="Left" Height="23" TextWrapping="Wrap" Text="{Binding Name}" VerticalAlignment="Top" Width="120" Margin="103,29,0,0"/>
        <TextBox HorizontalAlignment="Left" Height="23" Margin="103,97,0,0" Text="{Binding Text, ElementName=aaa}" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button Content="确定" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75" Margin="103,150,0,0" Click="Button_Click_1"/>

    </Grid>
</Window>

方法：
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.Shapes;

namespace 联系
{
    /// <summary>
    /// Window1.xaml 的交互逻辑
    /// </summary>
    public partial class Window1 : Window
    {
        DA da;
        public Window1()
        {

            InitializeComponent();
            da = new DA() { Name="admin",Pwd="123"};
            this.DataContext = da;
           
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            da.Name = DateTime.Now.ToString("HH:mm:ss:fff");
          
            
        }
    }
}