WPF PasswordBox进行数据绑定方法

public static string GetPasswordContent(DependencyObject obj) => (string)obj.GetValue(PasswordContentProperty);

public static void SetPasswordContent(DependencyObject obj, string value) => obj.SetValue(PasswordContentProperty, value);

public static readonly DependencyProperty PasswordContentProperty =
    DependencyProperty.RegisterAttached("PasswordContent", typeof(string), typeof(PasswordBoxBindingHelper),
    new PropertyMetadata(string.Empty, OnPasswordContentPropertyChanged));

private static void OnPasswordContentPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    var box = d as PasswordBox;
    box.PasswordChanged -= OnPasswordChanged;
    var password = (string)e.NewValue;
    if (box != null && box.Password != password)
        box.Password = password;
    box.PasswordChanged += OnPasswordChanged;
}

private static void OnPasswordChanged(object sender, RoutedEventArgs e)
{
    var box = sender as PasswordBox;
    SetPasswordContent(box, box.Password);
}

// xaml 绑定附加属性
<Window ...
        xmlns:local="clr-namespace:PasswordBoxBinding"
        Title="PasswordBoxBinding" Height="300" Width="450" WindowStartupLocation="CenterScreen">

    <Grid>
        <StackPanel HorizontalAlignment="Center" Orientation="Horizontal">
            <PasswordBox MinWidth="200" Height="30" BorderBrush="LightGray" BorderThickness="2"
                         local:PasswordBoxBindingHelper.PasswordContent="{Binding Password,Mode=TwoWay}"/>
            <Rectangle Width="20"/>
            <Button Width="80" Height="30" Content="查看密码" Command="{Binding ClickedCommand}"/>
        </StackPanel>
    </Grid>
</Window>

//xaml.cs 设置绑定源
public MainWindow()
{
    InitializeComponent();
    this.DataContext = new MainWindowViewModel();
}

// ViewModel
public class MainWindowViewModel : INotifyPropertyChanged
{
    public string Password
    {
        get => _password;
        set
        {
            _password = value;
            OnPropertyChanged();
        }
    }

    public DelegateCommand ClickedCommand => _clickedCommand ?? (_clickedCommand = new DelegateCommand { ExecuteAction = OnClicked });

    // 使用CallerMemberName特性简化代码，并可以避免手动输入错误
    public void OnPropertyChanged([CallerMemberName] string name = "") => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));

    private void OnClicked(object o) => MessageBox.Show($"password: {Password}");

    public event PropertyChangedEventHandler PropertyChanged;

    private DelegateCommand _clickedCommand;
    private string _password;
}

// 实现ICommand
public class DelegateCommand : ICommand
{
    public bool CanExecute(object parameter) => CanExecuteAction?.Invoke(parameter) ?? true;

    public void Execute(object parameter) => ExecuteAction?.Invoke(parameter);

    public event EventHandler CanExecuteChanged;

    public Action<object> ExecuteAction { get; set; }
    public Func<object, bool> CanExecuteAction { get; set; }
}