WPFPasswordBoxMVVM實現

2019-11-14 15:45:44

字體：大中小

來源：轉載

供稿：網友

由于PassWordBox.Password屬性非依賴屬性，所以不能作為綁定的目標，以下是本人的MVVM實現方法。

PasswordBox.Password與TextBox.Text同步，TextBox只是為了演示，實際使用的是TextBox.Text綁定的Source。

通過Behavior添加PasswordChanged事件的事件處理器，以及自定義一個附加屬性實現綁定，Behavior需要引用System.Windows.Interactivity.dll，代碼如下：

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代碼如下：

<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="350" Width="525">    <StackPanel>        <PasswordBox Margin="3" local:PasswordBoxHelper.Password="{Binding Path=Password,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">            <i:Interaction.Behaviors>                <local:PasswordBoxBehavior />            </i:Interaction.Behaviors>        </PasswordBox>        <TextBox Margin="3" 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 的交互邏輯    /// </summary>    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();            this.DataContext = new MainWindowViewModel();        }    }}

ViewModel引用Microsoft.Practices.Prism.dll，代碼如下：

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");                }            }        }    }}