1、继承属性变化接口

public partial class MainWindow : Window, INotifyPropertyChanged
{// 通知界面属性发生变化public event PropertyChangedEventHandler PropertyChanged;private void RaisePropertyChanged(string propertyName){PropertyChangedEventHandler handler = PropertyChanged;if(handler != null) handler(this, new PropertyChangedEventArgs(propertyName));}
}

2.创建被绑定属性

        // 创建被绑定的属性private string _userName;public string UserName{get { return _userName; }set { _userName = value;// 通知界面 属性发生变化RaisePropertyChanged("UserName");}}

3.界面绑定属性

            <!-- 绑定代码中的属性  UserName --><TextBox Text="{Binding UserName}" Grid.Row="0" Grid.Column="1" Margin="2"/>

4.界面数据关联属性

        public MainWindow(){InitializeComponent();// 为界面设置 绑定数据this.DataContext = this;}

5.使用绑定属性

// 获取界面输入
if (UserName == "WPF" && passWord == "123")
{   // 弹出一个新的界面 ctrl+ k + d//MessageBox.Show("OK");IndexWindow indexWindow = new IndexWindow();indexWindow.Show();// 隐藏登录界面this.Hide();
}
else
{// 警告框MessageBox.Show("输入的用户名或密码不正确");//txtUserName.Text = "";// 清空界面数据UserName = "";txtPassword.Text = "";
}

完整代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
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;namespace WPF_LoginUI
{/// <summary>/// MainWindow.xaml 的交互逻辑/// </summary>public partial class MainWindow : Window, INotifyPropertyChanged{public MainWindow(){InitializeComponent();// 为界面设置 绑定数据this.DataContext = this;}// 创建被绑定的属性private string _userName;public string UserName{get { return _userName; }set { _userName = value;// 通知界面 属性发生变化RaisePropertyChanged("UserName");}}// 被用来 界面绑定的属性//public string UserName { get; set; } = "WPF";public event PropertyChangedEventHandler PropertyChanged;private void RaisePropertyChanged(string propertyName){PropertyChangedEventHandler handler = PropertyChanged;if(handler != null) handler(this, new PropertyChangedEventArgs(propertyName));}/// <summary>/// 按钮 登录/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void BtnLogin_Click(object sender, RoutedEventArgs e){//string userName = txtUserName.Text;string passWord = txtPassword.Text;if (UserName == "WPF" && passWord == "123"){   // 弹出一个新的界面 ctrl+ k + d//MessageBox.Show("OK");IndexWindow indexWindow = new IndexWindow();indexWindow.Show();// 隐藏登录界面this.Hide();}else{// 警告框MessageBox.Show("输入的用户名或密码不正确");//txtUserName.Text = "";UserName = "";txtPassword.Text = "";}}}
}