WPF - Bindable PasswordBox

WPF - Bindable PasswordBox

using System.Windows;
using System.Windows.Controls;

namespace CustomControl
{
    public class BindablePasswordBox : Decorator
    {
        /// <summary>
        /// The password dependency property.
        /// </summary>
        public static readonly DependencyProperty PasswordProperty;

        private bool isPreventCallback;
        private RoutedEventHandler savedCallback;

        /// <summary>
        /// Static constructor to initialize the dependency properties.
        /// </summary>
        static BindablePasswordBox()
        {
            PasswordProperty = DependencyProperty.Register(
                "Password",
                typeof(string),
                typeof(BindablePasswordBox),
                new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, new PropertyChangedCallback(OnPasswordPropertyChanged))
            );
        }

        /// <summary>
        /// Saves the password changed callback and sets the child element to the password box.
        /// </summary>
        public BindablePasswordBox()
        {
            savedCallback = HandlePasswordChanged;

            PasswordBox passwordBox = new PasswordBox();
            passwordBox.PasswordChanged += savedCallback;
            Child = passwordBox;
        }

        /// <summary>
        /// The password dependency property.
        /// </summary>
        public string Password
        {
            get { return GetValue(PasswordProperty) as string; }
            set { SetValue(PasswordProperty, value); }
        }

        /// <summary>
        /// Handles changes to the password dependency property.
        /// </summary>
        /// <param name="d">the dependency object</param>
        /// <param name="eventArgs">the event args</param>
        private static void OnPasswordPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs eventArgs)
        {
            BindablePasswordBox bindablePasswordBox = (BindablePasswordBox) d;
            PasswordBox passwordBox = (PasswordBox) bindablePasswordBox.Child;

            if (bindablePasswordBox.isPreventCallback)
            {
                return;
            }

            passwordBox.PasswordChanged -= bindablePasswordBox.savedCallback;
            passwordBox.Password = (eventArgs.NewValue != null) ? eventArgs.NewValue.ToString() : "";
            passwordBox.PasswordChanged += bindablePasswordBox.savedCallback;
        }

        /// <summary>
        /// Handles the password changed event.
        /// </summary>
        /// <param name="sender">the sender</param>
        /// <param name="eventArgs">the event args</param>
        private void HandlePasswordChanged(object sender, RoutedEventArgs eventArgs)
        {
            PasswordBox passwordBox = (PasswordBox) sender;

            isPreventCallback = true;
            Password = passwordBox.Password;
            isPreventCallback = false;
        }
    }
}

This is a workaround for the fact that the Password property of System.Windows.Controls.PasswordBox is not a DependencyProperty. This creates a new BindablePasswordBox using System.Windows.Controls.Decorator.

How do I expose the "Padding" property of the underlying PasswordBox?

I tried to add a new DependencyProperty "PaddingProperty":

public static readonly DependencyProperty PaddingProperty = DependencyProperty.Register(
    "Padding", typeof(double), typeof(BindablePasswordBox),
    new FrameworkPropertyMetadata(new Thickness(2), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, new PropertyChangedCallback(OnPaddingPropertyChanged))
);

public Thickness Padding
{
    get { return (Thickness)GetValue(PaddingProperty); }
    set { SetValue(PaddingProperty, value); }
}

but I cannot set it in XAML, says something about type mismatch.

Is there an attribute I can add to the Padding property so WPF will accept my values in xaml?

example xaml:

                <UniformGrid>
                    <Label VerticalAlignment="Center" HorizontalAlignment="Right">Password</Label>
                    <PasswordBox Height="20" Width="70" HorizontalAlignment="Left"></PasswordBox>
                </UniformGrid>

@dtaylor-530 sorry to bother but something very weird happens to me. Ive added the code and the extension
<PasswordBox Margin="{StaticResource SmallTopMargin}" h:PasswordHelper.Attach="True" h:PasswordHelper.Password="{Binding BackupPassword, Mode=TwoWay}" mah:TextBoxHelper.UseFloatingWatermark="True" mah:TextBoxHelper.Watermark="{x:Static properties:Resources.SettingsPageBackupPwd}" Style="{StaticResource MahApps.Styles.PasswordBox.Button.Revealed}" ToolTip="{x:Static properties:Resources.SettingsPageBackupPwdTooltip}" />

I've put it in the settings page of a standard WPF app created with the visual studio template for Core 3.1
But when I leave the page I get an "empty" password:
BackupPassword >t< BackupPassword >te< BackupPassword >tes< BackupPassword >test< BackupPassword >< navigated from

to debug it I've added:
private string _backupPassword; public string BackupPassword { get { return _backupPassword; } set { Debug.WriteLine("BackupPassword >" + value+ "<"); Set(ref _backupPassword, value); } }

I'm using MVVM Light

@dtaylor-530 sorry to bother but something very weird happens to me. Ive added the code and the extension
<PasswordBox Margin="{StaticResource SmallTopMargin}" h:PasswordHelper.Attach="True" h:PasswordHelper.Password="{Binding BackupPassword, Mode=TwoWay}" mah:TextBoxHelper.UseFloatingWatermark="True" mah:TextBoxHelper.Watermark="{x:Static properties:Resources.SettingsPageBackupPwd}" Style="{StaticResource MahApps.Styles.PasswordBox.Button.Revealed}" ToolTip="{x:Static properties:Resources.SettingsPageBackupPwdTooltip}" />

I've put it in the settings page of a standard WPF app created with the visual studio template for Core 3.1
But when I leave the page I get an "empty" password:
BackupPassword >t< BackupPassword >te< BackupPassword >tes< BackupPassword >test< BackupPassword >< navigated from

to debug it I've added:
private string _backupPassword; public string BackupPassword { get { return _backupPassword; } set { Debug.WriteLine("BackupPassword >" + value+ "<"); Set(ref _backupPassword, value); } }

I'm using MVVM Light

@msavazzi hi
If your still having difficulties with this problem then i can take a look at what you have so far. I tried to clone your repository @https://github.com/msavazzi/Mahapps.PasswordBind but there were files missing including the UserControl with the PasswordBox.

@dtaylor-530 still have the issue. Weird for the project as I just dumped the (clear) solution folder on git. Let me know if you need more info