Question

I’m creating a custom control that has a PasswordBox in it. How do I hook up a DependencyProperty of my custom control to the Password property of the PasswordBox?

From all the examples I see, hooking it up the password in the template using TemplateBinding should do the trick, but this doesn’t seem to be working. What am I missing?

generic.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:CustomControlBinding="clr-namespace:CustomControlBinding">

    <Style TargetType="CustomControlBinding:PasswordBoxTest">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="CustomControlBinding:PasswordBoxTest">
                    <Grid Background="Transparent">
                        <PasswordBox Password="{TemplateBinding Text}" />
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>

PasswordBoxTest.cs

namespace CustomControlBinding
{
    public class PasswordBoxTest : Control
    {
        public static readonly DependencyProperty TextProperty = DependencyProperty.Register( "Text", typeof( string ), typeof( PasswordBoxTest ), new PropertyMetadata( OnTextPropertyChanged ) );

        public string Text
        {
            get { return GetValue( TextProperty ) as string; }
            set { SetValue( TextProperty, value ); }
        }

        public PasswordBoxTest()
        {
            DefaultStyleKey = typeof( PasswordBoxTest );
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
        }

        private static void OnTextPropertyChanged( DependencyObject sender, DependencyPropertyChangedEventArgs e )
        {
        }
    }
}

Answer 1

I haven’t been able to get this to work no matter what I do. What I did instead that does work is setting up some fake binding in code.

namespace CustomControlBinding
{
    public class PasswordBoxTest : Control
    {
        private PasswordBox passwordBox;
        private string passwordSetBeforeTemplateApplied;

        public static readonly DependencyProperty PasswordProperty = DependencyProperty.Register( "Password", typeof( string ), new PropertyMetadata( OnPasswordPropertyChanged ) );

        public string Password
        {
            get { return GetValue( PasswordProperty ) as string; }
            set { SetValue( PasswordProperty, value ); }
        }

        public PasswordBoxTest()
        {
            DefaultStyleKey = typeof( PasswordBoxTest );
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            passwordBox = (PasswordBox)GetTemplateChild( "PasswordElement" );
            passwordBox.PasswordChanged += PasswordBoxPasswordChanged;
            if( !string.IsNullOrEmpty( passwordSetBeforeTemplateApplied ) )
            {
                passwordBox.Password = passwordSetBeforeTemplateApplied;
            }
        }

        public static void OnPasswordPropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e )
        {
            ( (WatermarkPasswordBox)d ).OnPasswordChanged( d, e );
        }

        private void OnPasswordChanged(  DependencyObject d, DependencyPropertyChangedEventArgs e )
        {
            if( passwordBox == null )
            {
                passwordSetBeforeTemplateApplied = Password;
                return;
            }

            if( Password != passwordBox.Password )
            {
                passwordBox.Password = Password;
            }
        }

        private void PasswordBoxPasswordChanged( object sender, RoutedEventArgs e )
        {
            if( passwordBox.Password != Password )
            {
                Password = passwordBox.Password;
            }
        }    
    }
}