进一步学习 CommunityToolkit.Mvvm

private string title;

public string Title

{
    get;set;
}

[ObservableProperty]
private string title;

        private bool isEnabled;
        public bool IsEnabled
        {
            get => isEnabled;
            set
            {
                isEnabled = value;
                OnPropertyChanged(nameof(IsEnabled));
                //以上两句可由以下替代
                //SetProperty(ref isEnabled, value);

                ButtonClickCommand.NotifyCanExecuteChanged();
            }
        }

        public RelayCommand ButtonClickCommond { get; }
        public MainWindowViewModel()
        {
           ButtonClickCommond = new RelayCommand(() => { Debug.WriteLine("Button clicked."); Title = "good"; }, () => IsEnabled);
        }    

[ObservableProperty]
[NotifyCanExecuteChangedFor(nameof(ButtonClickCommand))]
private bool isEnabled;

 [RelayCommand(CanExecute = nameof(IsEnabled))]  //[RelayCommand(CanExecute = nameof(CanButtonClick))]
 private void ButtonClick()
 {
     Debug.WriteLine("Button clicked."); 
     Title = "good";
 }

//private bool CanButtonClick()
//{
//    return IsEnabled;
//}

        [RelayCommand(CanExecute = nameof(IsEnabled))]
        private async Task ButtonClickAsync()//会自动将当前按钮设置CanExecute 设置为False退出时设置回True
        {
            await Task.Delay(1000);
            Title = "good";
        }

<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>

<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
    <TextBox Width="200" Text="{Binding Title}" />
    <CheckBox Content="is Enabled" IsChecked="{Binding IsEnabled}" />
    <Button Command="{Binding ButtonClickCommand}" Content="ok" />
</StackPanel>

            <CheckBox
                VerticalContentAlignment="Center"
                Content="Is Running"
                IsChecked="{Binding ButtonClickCommand.IsRunning, Mode=OneWay}" />

        [ObservableProperty]
        [NotifyPropertyChangedFor(nameof(Caption))]
        private string title = "hello world";
        public string Caption => $"Title:{Title}";