PasswordBox validation

本文关键字：validation PasswordBox | 更新日期: 2023-09-27 17:49:20

PasswordBox元素的Password属性不是DependencyObject，因此不能被绑定(没有Text属性)。通过将消息附加到PasswordChanged事件，传递源并在视图模型中抓取它，可以捕获用户类型的密码。然而，缺乏绑定意味着没有机会设置ValidatesOnDataErrors=True，因此IDataErrorInfo方法永远不会调用，这意味着任何错误模板永远不会激活。有人知道怎么解决这个问题吗?也就是说，是否有另一种方法让元素调用对IDataErrorInfo索引器的视图模型的调用?

一个合理的问题可能是为什么要验证密码。

两个原因:

1)让用户知道密码是必需的

2)让用户知道密码和密码确认是否相同

PasswordBox validation

这里也是一个很好的答案:http://wpftutorial.net/PasswordBox.html但是，如果这样做，密码将以纯文本形式存储在内存中。

也许最好将附加属性"Password"从示例更改为"IsEmpty"answers"PasswordHash"。

继Alex的回答之后，我也使用了本文中的信息;

http://wpftutorial.net/PasswordBox.html

我做了以下允许验证的操作;

XAML: 

<Grid Grid.Row="2" Grid.Column="1">
    <TextBox x:Name="plain1" Text="{Binding Password, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True,NotifyOnValidationError=True}" Visibility="Hidden" />
    <PasswordBox x:Name="PasswordHelperBox" w:PasswordHelper.Attach="True" w:PasswordHelper.Password="{Binding Text, ElementName=plain1, Mode=TwoWay}" TabIndex="2" Margin="0,2,30,2"/>
</Grid>

其中Password是要绑定的属性。

助手类;

public static class PasswordHelper
{
    public static readonly DependencyProperty PasswordProperty =
        DependencyProperty.RegisterAttached("Password",
        typeof(string), typeof(PasswordHelper),
        new FrameworkPropertyMetadata(string.Empty, OnPasswordPropertyChanged));
    public static readonly DependencyProperty AttachProperty =
        DependencyProperty.RegisterAttached("Attach",
        typeof(bool), typeof(PasswordHelper), new PropertyMetadata(false, Attach));
    private static readonly DependencyProperty IsUpdatingProperty =
       DependencyProperty.RegisterAttached("IsUpdating", typeof(bool), 
       typeof(PasswordHelper));

    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)
    {
        PasswordBox 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)
    {
        PasswordBox 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)
    {
        PasswordBox passwordBox = sender as PasswordBox;
        SetIsUpdating(passwordBox, true);
        SetPassword(passwordBox, passwordBox.Password);
        SetIsUpdating(passwordBox, false);
    }
}
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