WPF最基本的原理代码(MVVM)

这个代码实现的功能是，按“测试”按钮，显示单词“Hello World”，它是WPF最核心的原理代码。用绑定控制数据，用命令代替事件。
XAML界面代码如下：

<Window x:Class="WpfApp2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <StackPanel>
        <Button Content="测试" Height="30" Width="100" Command="{Binding ShowCommand}"/>
        <Label Content="{Binding Name}" HorizontalContentAlignment="Center"/>
    </StackPanel>
</Window>

类代码如下：

using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Input;

namespace WpfApp2
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext=new ViewModel();
        }
    }
    //继承INotifyPropertyChanged接口，用来实现界面跟随属性的改变而改变。
    //之所以做成父类，是为了实现代码复用
    public class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged([CallerMemberName]string propertyName="")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
    //绑定数据源的类，包括属性和命令
    public class ViewModel:ViewModelBase
    {
        public ViewModel()
        {
            ShowCommand = new MyCommand(ShowEvent);
        }
        private string name = "默认值";
        public string Name { get { return name; } set { name = value;OnPropertyChanged(); } }
        public MyCommand ShowCommand { get; set; }
        public void ShowEvent()
        {
            Name = "Hello world";
        }
    }
    //命令类
    public class MyCommand : ICommand
    {
        private Action action;
        public MyCommand(Action action)
        {
            this.action = action;
        }
        public event EventHandler CanExecuteChanged;
        public bool CanExecute(object parameter)
        {
            return true;
        }
        public void Execute(object parameter)
        {
            action?.Invoke();
        }
    }
}