WPF Watermark PasswordBox de Watermark TextBox

Question

J'utilise une zone de texte de filigrane comme dans TextBox de filigrane dans WPF

 <Grid Grid.Row="0" Background="{StaticResource brushWatermarkBackground}" Style="{StaticResource EntryFieldStyle}" >
        <TextBlock Margin="5,2" Text="This prompt dissappears as you type..." Foreground="{StaticResource brushWatermarkForeground}"
                   Visibility="{Binding ElementName=txtUserEntry, Path=Text.IsEmpty, Converter={StaticResource BooleanToVisibilityConverter}}" />
        <TextBox Name="txtUserEntry" Background="Transparent" BorderBrush="{StaticResource brushWatermarkBorder}" />
    </Grid>

Comment puis-je appliquer cela à une PasswordBox?

Answer 1

L’approche générale est la même: vous écrivez un style de contrôle personnalisé et affichez un filigrane chaque fois que la case du mot de passe est vide. Le seul problème ici est que la propriété PasswordBox.Password n'est pas une propriété de dépendance et que vous ne pouvez pas l'utiliser dans le déclencheur. De plus, PasswordBox est scellé, vous ne pouvez donc pas remplacer ce comportement de notification. Mais vous pouvez utiliser les propriétés attachées ici. Le code suivant montre comment.

XAML

<Window x:Class="WpfTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:WpfTest="clr-namespace:WpfTest"
    Title="Password Box Sample" Height="300" Width="300">
  <Window.Resources>
    <Style x:Key="{x:Type PasswordBox}"
        TargetType="{x:Type PasswordBox}">
      <Setter Property="WpfTest:PasswordBoxMonitor.IsMonitoring"
              Value="True"/>
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="{x:Type PasswordBox}">
            <Border Name="Bd"
                    Background="{TemplateBinding Background}"
                    BorderThickness="{TemplateBinding BorderThickness}"
                    BorderBrush="{TemplateBinding BorderBrush}"
                    SnapsToDevicePixels="true">
              <Grid>
                <ScrollViewer x:Name="PART_ContentHost"
                              SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                <TextBlock Text="Please enter your password" 
                           Margin="4, 2, 0, 0"
                           Foreground="Gray" 
                           Visibility="Collapsed"
                           Name="txtPrompt" />
              </Grid>
            </Border>
            <ControlTemplate.Triggers>
              <Trigger Property="IsEnabled"
                                         Value="false">
                <Setter TargetName="Bd"
                                            Property="Background"
                                            Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
                <Setter Property="Foreground"
                                            Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
              </Trigger>
              <Trigger Property="WpfTest:PasswordBoxMonitor.PasswordLength" Value="0">
                <Setter Property="Visibility" TargetName="txtPrompt" Value="Visible"/>
              </Trigger>
            </ControlTemplate.Triggers>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </Window.Resources>
  <Grid>
    <PasswordBox VerticalAlignment="Top"/>
  </Grid>
</Window>

C #

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

namespace WpfTest
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

    }

  public class PasswordBoxMonitor : DependencyObject
  {
    public static bool GetIsMonitoring(DependencyObject obj)
    {
      return (bool)obj.GetValue(IsMonitoringProperty);
    }

    public static void SetIsMonitoring(DependencyObject obj, bool value)
    {
      obj.SetValue(IsMonitoringProperty, value);
    }

    public static readonly DependencyProperty IsMonitoringProperty =
        DependencyProperty.RegisterAttached("IsMonitoring", typeof(bool), typeof(PasswordBoxMonitor), new UIPropertyMetadata(false, OnIsMonitoringChanged));



    public static int GetPasswordLength(DependencyObject obj)
    {
      return (int)obj.GetValue(PasswordLengthProperty);
    }

    public static void SetPasswordLength(DependencyObject obj, int value)
    {
      obj.SetValue(PasswordLengthProperty, value);
    }

    public static readonly DependencyProperty PasswordLengthProperty =
        DependencyProperty.RegisterAttached("PasswordLength", typeof(int), typeof(PasswordBoxMonitor), new UIPropertyMetadata(0));

    private static void OnIsMonitoringChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
      var pb = d as PasswordBox;
      if (pb == null)
      {
        return;
      }
      if ((bool) e.NewValue)
      {
        pb.PasswordChanged += PasswordChanged;
      }
      else
      {
        pb.PasswordChanged -= PasswordChanged;
      }
    }

    static void PasswordChanged(object sender, RoutedEventArgs e)
    {
      var pb = sender as PasswordBox;
      if (pb == null)
      {
        return;
      }
      SetPasswordLength(pb, pb.Password.Length);
    }
  }
}

Veuillez noter PasswordBoxMonitor en code XAML.

Answer 2

vous pouvez afficher / masquer l'arrière-plan par vous-même au lieu d'utiliser des déclencheurs:

XAML:

<PasswordBox x:Name="passwordBox" PasswordChanged="passwordChanged" 
        Background="{StaticResource PasswordHint}" />

Code derrière:

// helper to hide watermark hint in password field
private void passwordChanged(object sender, RoutedEventArgs e)
{           
    if (passwordBox.Password.Length == 0)
        passwordBox.Background.Opacity = 1;
    else
        passwordBox.Background.Opacity = 0;
}

Answer 3

vous pouvez utiliser mon approche pour un comportement en filigrane. tout ce que vous avez à faire est de copier et coller le TextBoxWatermarkBehavior et de changer le Behavior<TextBox> en Behavior<PasswordBox>.

vous pouvez trouver un projet de démonstration ici

Answer 4

La suggestion proposée par @ blindmeis est bonne . Pour PasswordBox, la classe serait la suivante.

public class PasswordBoxWatermarkBehavior : System.Windows.Interactivity.Behavior<PasswordBox>
{
    private TextBlockAdorner adorner;
    private WeakPropertyChangeNotifier notifier;

    #region DependencyProperty's

    public static readonly DependencyProperty LabelProperty =
        DependencyProperty.RegisterAttached("Label", typeof(string), typeof(PasswordBoxWatermarkBehavior));

    public string Label
    {
        get { return (string)GetValue(LabelProperty); }
        set { SetValue(LabelProperty, value); }
    }

    public static readonly DependencyProperty LabelStyleProperty =
        DependencyProperty.RegisterAttached("LabelStyle", typeof(Style), typeof(PasswordBoxWatermarkBehavior));

    public Style LabelStyle
    {
        get { return (Style)GetValue(LabelStyleProperty); }
        set { SetValue(LabelStyleProperty, value); }
    }

    #endregion

    protected override void OnAttached()
    {
        base.OnAttached();
        this.AssociatedObject.Loaded += this.AssociatedObjectLoaded;
        this.AssociatedObject.PasswordChanged += AssociatedObjectPasswordChanged;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        this.AssociatedObject.Loaded -= this.AssociatedObjectLoaded;
        this.AssociatedObject.PasswordChanged -= this.AssociatedObjectPasswordChanged;

        this.notifier = null;
    }

    private void AssociatedObjectPasswordChanged(object sender, RoutedEventArgs e)
    {
        this.UpdateAdorner();
    }

    private void AssociatedObjectLoaded(object sender, System.Windows.RoutedEventArgs e)
    {
        this.adorner = new TextBlockAdorner(this.AssociatedObject, this.Label, this.LabelStyle);

        this.UpdateAdorner();

        //AddValueChanged for IsFocused in a weak manner
        this.notifier = new WeakPropertyChangeNotifier(this.AssociatedObject, UIElement.IsFocusedProperty);
        this.notifier.ValueChanged += new EventHandler(this.UpdateAdorner);
    }

    private void UpdateAdorner(object sender, EventArgs e)
    {
        this.UpdateAdorner();
    }


    private void UpdateAdorner()
    {
        if (!String.IsNullOrEmpty(this.AssociatedObject.Password) || this.AssociatedObject.IsFocused)
        {
            // Hide the Watermark Label if the adorner layer is visible
            this.AssociatedObject.TryRemoveAdorners<TextBlockAdorner>();
        }
        else
        {
            // Show the Watermark Label if the adorner layer is visible
            this.AssociatedObject.TryAddAdorner<TextBlockAdorner>(adorner);
        }
    }
}