wpf登陆及构造函数的传值及绑定传值

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;

namespace ceshi
{
    public class user : INotifyPropertyChanged
    {
        private string username;

        public string Username
        {
            get { return username; }
            set {
                username = value;
                OnPropertyChanged("Username");
                
            }
        }
        private int usercode;

        public int Usercode
        {
            get { return usercode; }
            set { usercode = value; }
        }
        private string password;

        public string Password
        {
            get { return password; }
            set {
                password = value;
                OnPropertyChanged("Password");
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;//事件委托
//所谓“事件委托”，一个事件的本质是一个委托（因为事件是委托类型的）。而委托的好处在于它可以动态调用不同类之间具备相同函数签名（函数参数顺序、类型、个数相同），且函数返回值必须完全相同的函数。
        public virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

<Window x:Class="WpfApplication3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="主页" Height="349.189" Width="387.111" HorizontalContentAlignment="Stretch" Background="#FFB58585" WindowStyle="ToolWindow">
    <Grid Margin="39,31,50.8,31.6">
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="120"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <Label Content="用户名" HorizontalAlignment="Right"  VerticalAlignment="Top" Margin="31,34,0,0"/>
        <Label Content="密码" HorizontalAlignment="Right"  Grid.Row="1" VerticalAlignment="Top" Margin="31,24.8,0,0" RenderTransformOrigin="0.175,0.555"/>
        <TextBox x:Name="user" HorizontalAlignment="Left" Height="23" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="120" Margin="3,37,0,0" RenderTransformOrigin="0.728,0.39" Grid.Column="1"/>
        <Button Content="登陆" HorizontalAlignment="Left" Grid.ColumnSpan="2" Grid.Row="2" VerticalAlignment="Top" Width="75" Margin="10,37.6,0,0" Click="Button_Click_2" Grid.Column="1"/>
        <PasswordBox x:Name="pwd" Grid.Column="1" HorizontalAlignment="Left" Margin="5,25.8,0,0" Grid.Row="1" VerticalAlignment="Top" Width="118" Height="25"/>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 ceshi;

namespace WpfApplication3
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
        user r = new user();//实例化新对像
        public Window1 w;
        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            //r = new user();
            r.Username = "admin";//记录用户名和密码
            r.Password = "admin";
            if (string.IsNullOrWhiteSpace(user.Text))
            {
                MessageBox.Show("请输入用户名和密码");
            }
            else if (user.Text.ToUpper()==r.Username.ToUpper()&&pwd.Password==r.Password)
            {
                if (w==null)//如果为空  新实例化一个
                {
                    
                    w = new Window1(r); 
                    w.Show();
                    this.Owner = w;
                    this.Hide();
                }
            }
            else
            {
                 MessageBox.Show("登录失败");
            }
        }
    }
}

<Window x:Class="WpfApplication3.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>
        <TextBox x:Name="a" HorizontalAlignment="Left" Height="23" Margin="83,52,0,0" TextWrapping="Wrap" Text="{Binding  Username}" VerticalAlignment="Top" Width="120"/>
        <TextBox x:Name="b" HorizontalAlignment="Left" Height="23" Margin="83,132,0,0" TextWrapping="Wrap" Text="{Binding Password}" VerticalAlignment="Top" Width="120"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="193,194,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_1"/>

    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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;
using ceshi;

namespace WpfApplication3
{
    /// <summary>
    /// Window1.xaml 的交互逻辑
    /// </summary>
    public partial class Window1 : Window
    {
        public MainWindow wd;
        //public Window1(MainWindow w)//构造函数传值传的是整个页面
        //{
        //    InitializeComponent();
        //    wd = w;
        //    a.Text = wd.user.Text;
        //    b.Text = wd.user.Text;
        //}
        user uu;
        public Window1(user u)
        {
            uu = u;
            InitializeComponent();
            a.DataContext = u;//绑定传值
            //b.DataContext = u;
            b.SetBinding(TextBox.TextProperty,
               new Binding("Username") { Source = uu, Mode = BindingMode.TwoWay });

            //a.Text = u.Username;//构造函数传值
            //b.Text = u.Password;
        }
        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            uu.Username = DateTime.Now.ToString("HH:mm:ss.fff");
        }
    }
}