在WPF中使用密码文本框Binding的方法

概述

在WPF中使用密码文本框Binding的方法。

解释

public static class PasswordBoxAssistantHelper {

    public static readonly DependencyProperty PasswordProperty =
        DependencyProperty.RegisterAttached("Password",
        typeof(string), typeof(PasswordBoxAssistantHelper),
        new FrameworkPropertyMetadata(string.Empty, OnPasswordPropertyChanged));

    public static readonly DependencyProperty AttachProperty =
        DependencyProperty.RegisterAttached("Attach",
        typeof(bool), typeof(PasswordBoxAssistantHelper), new PropertyMetadata(false, Attach));

    private static readonly DependencyProperty IsUpdatingProperty =
        DependencyProperty.RegisterAttached("IsUpdating", typeof(bool),
        typeof(PasswordBoxAssistantHelper));

    public static void SetAttach(DependencyObject dp, bool value) {
        dp.SetValue(AttachProperty, value);
    }

    public static bool GetAttach(DependencyObject dp) {
        return (bool)dp.GetValue(AttachProperty);
    }

    public static string GetPassword(DependencyObject dp) {
        return (string)dp.GetValue(PasswordProperty);
    }

    public static void SetPassword(DependencyObject dp, string value) {
        dp.SetValue(PasswordProperty, value);
    }

    private static bool GetIsUpdating(DependencyObject dp) {
        return (bool)dp.GetValue(IsUpdatingProperty);
    }

    private static void SetIsUpdating(DependencyObject dp, bool value) {
        dp.SetValue(IsUpdatingProperty, value);
    }

    private static void OnPasswordPropertyChanged(DependencyObject sender,
        DependencyPropertyChangedEventArgs e) {
        var passwordBox = sender as PasswordBox;
        passwordBox.PasswordChanged -= PasswordChanged;

        if (!(bool)GetIsUpdating(passwordBox)) {
            passwordBox.Password = (string)e.NewValue;
        }

        passwordBox.PasswordChanged += PasswordChanged;
    }

    private static void Attach(DependencyObject sender,
        DependencyPropertyChangedEventArgs e) {
        var passwordBox = sender as PasswordBox;

        if (passwordBox == null)
            return;
        if ((bool)e.OldValue) {
            passwordBox.PasswordChanged -= PasswordChanged;
        }
        if ((bool)e.NewValue) {
            passwordBox.PasswordChanged += PasswordChanged;
        }
    }

    private static void PasswordChanged(object sender, RoutedEventArgs e) {
        var passwordBox = sender as PasswordBox;

        SetIsUpdating(passwordBox, true);
        SetPassword(passwordBox, passwordBox.Password);
        SetIsUpdating(passwordBox, false);
    }

}

xmlns:pwdHelper="clr-namespace:[自己的命名空间];assembly=[自己的程序集名]"

<PasswordBox pwdHelper:PasswordBoxAssistantHelper.Password="{Binding Password}" />