.net 使用ReactiveUI与PasswordBox进行双向绑定

我遇到了一个问题，如何在

PasswordBox

中以双向方式正确绑定密码。我目前的解决方案几乎奏效。它的问题是，在键入过程中，光标停留在开头，而不是跟文本在结尾。键入

12345

，我的视图模型接收值

54321

我正在使用WFP和XAML。视图背后的代码如下所示：

Observable.FromEventPattern(SecretKey, nameof(SecretKey.PasswordChanged))
    .Subscribe(evt => ViewModel.SecretKey = SecretKey.Password)
    .DisposeWith(disposableRegistration);

this.OneWayBind(ViewModel, viewModel => viewModel.SecretKey, view => view.SecretKey.Password)
    .DisposeWith(disposableRegistration);

---

当其中一个结构被注释时，游标的行为是正确的，所以问题在于以两种方式绑定，我不知道如何解决它。正如您现在所看到的那样，PasswordBox.Password不能从视图绑定到视图模型，我需要使用事件。

我认为没有“官方”的方法，我不确定您是否应该这样做。
但您可以在设置值后手动设置光标位置以解决此问题（）

“黑客”绑定：

this.WhenAnyValue(x => x.ViewModel.SecretKey)
    .Where(pw => pw != null)
    .Do(pw =>
    {
        secretKey.Password = pw;
        SetCursor(secretKey, pw.Length);
    })
    .Subscribe()
    .DisposeWith(disposableRegistration);

---

PasswordBox

通常由附加属性处理。我做了研究，

ReactiveUi

binding不能处理带有附加属性的双向绑定。另一方面，当您使用

ReactiveUi

时，XAML中的绑定没有危险信号-这是不鼓励的，但不是禁止的。请记住，纯

ReactiveUi

无法实现附加属性，我决定在绑定

密码箱时破例，我认为这是合理和正确的

我使用了
PasswordHelper
，它实现了上教程中的附加属性

在XAML中，我使用带有附加属性的
密码箱的标准绑定：

<PasswordBox Name="PasswordBox"
             local:PasswordHelper.Attach="True"
             local:PasswordHelper.Password="{Binding Password, Mode=TwoWay}"/>

您可以在中找到示例应用程序

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);
    }
}

<PasswordBox Name="PasswordBox"
             local:PasswordHelper.Attach="True"
             local:PasswordHelper.Password="{Binding Password, Mode=TwoWay}"/>

this.WhenActivated(d =>
{
    this.WhenAnyValue(x => x.ViewModel).BindTo(this, x => x.DataContext).DisposeWith(d);
});