WPF PasswordBox MVVM 实现

由于PasswordBox.Password属性非依赖属性，所以不能作为绑定的目标，以下是本人的MVVM实现方法。

PasswordBox.Password与TextBox.Text同步，TextBox只是为了演示，实际使用的是TextBox.Text绑定的Source。

通过Behavior添加PasswordChanged事件的事件处理器，以及自定义一个附加属性实现绑定，Behavior需要引用System.Windows.Interactivity.dll，代码如下：

using System.Windows;

using System.Windows.Controls;

using System.Windows.Interactivity;

namespace PasswordHelperTest

{

    public static class PasswordBoxHelper

    {

        public static readonly DependencyProperty PasswordProperty =

            DependencyProperty.RegisterAttached("Password",

            typeof(string), typeof(PasswordBoxHelper),

            new FrameworkPropertyMetadata(string.Empty, OnPasswordPropertyChanged));

        private static void OnPasswordPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)

        {

            PasswordBox passwordBox = sender as PasswordBox;

            string password = (string)e.NewValue;

            if (passwordBox != null && passwordBox.Password != password)

            {

                passwordBox.Password = password;

            }

        }

        public static string GetPassword(DependencyObject dp)

        {

            return (string)dp.GetValue(PasswordProperty);

        }

        public static void SetPassword(DependencyObject dp, string value)

        {

            dp.SetValue(PasswordProperty, value);

        }

    }

    public class PasswordBoxBehavior : Behavior<PasswordBox>

    {

        protected override void OnAttached()

        {

            base.OnAttached();

            AssociatedObject.PasswordChanged += OnPasswordChanged;

        }

        private static void OnPasswordChanged(object sender, RoutedEventArgs e)

        {

            PasswordBox passwordBox = sender as PasswordBox;

            string password = PasswordBoxHelper.GetPassword(passwordBox);

            if (passwordBox != null && passwordBox.Password != password)

            {

                PasswordBoxHelper.SetPassword(passwordBox, passwordBox.Password);

            }

        }

        protected override void OnDetaching()

        {

            base.OnDetaching();

            AssociatedObject.PasswordChanged -= OnPasswordChanged;

        }

    }

}

View代码如下：

<Window x:Class="PasswordHelperTest.MainWindow"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

        xmlns:local="clr-namespace:PasswordHelperTest"

        Title="MainWindow" Height="" Width="">

    <StackPanel>

        <PasswordBox Margin="" local:PasswordBoxHelper.Password="{Binding Path=Password,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">

            <i:Interaction.Behaviors>

                <local:PasswordBoxBehavior />

            </i:Interaction.Behaviors>

        </PasswordBox>

        <TextBox Margin="" Text="{Binding Path=Password,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"></TextBox>

    </StackPanel>

</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;

namespace PasswordHelperTest

{

    /// <summary>

    /// MainWindow.xaml 的交互逻辑

    /// </summary>

    public partial class MainWindow : Window

    {

        public MainWindow()

        {

            InitializeComponent();

            this.DataContext = new MainWindowViewModel();

        }

    }

}

ViewModel引用Microsoft.Practices.Prism.dll，代码如下：

using Microsoft.Practices.Prism.ViewModel;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace PasswordHelperTest

{

    class MainWindowViewModel : NotificationObject

    {

        private string _password;

        public string Password

        {

            get { return _password; }

            set

            {

                if (_password != value)

                {

                    _password = value;

                    this.RaisePropertyChanged("Password");

                }

            }

        }

    }

}

巴特西

WPF PasswordBox MVVM 实现

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