WPF में वॉटरमार्क/संकेत टेक्स्ट/प्लेसहोल्डर टेक्स्टबॉक्स




textbox watermark (20)

शैली का उपयोग कर सरल समाधान:

    <TextBox>
        <TextBox.Style>
            <Style TargetType="TextBox" xmlns:sys="clr-namespace:System;assembly=mscorlib">
                <Style.Resources>
                    <VisualBrush x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
                        <VisualBrush.Visual>
                            <Label Content="MM:SS:HH AM/PM" Foreground="LightGray" />
                        </VisualBrush.Visual>
                    </VisualBrush>
                </Style.Resources>
                <Style.Triggers>
                    <Trigger Property="Text" Value="{x:Static sys:String.Empty}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="Text" Value="{x:Null}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="True">
                        <Setter Property="Background" Value="White" />
                    </Trigger>
                </Style.Triggers>
            </Style>
        </TextBox.Style>
    </TextBox>

महान समाधान:

https://code.msdn.microsoft.com/windowsdesktop/In-place-hit-messages-for-18db3a6c

मैं कुछ टेक्स्ट को टेक्स्टबॉक्स में कैसे डाल सकता हूं जिसे उपयोगकर्ता स्वचालित रूप से हटा देता है जब उपयोगकर्ता इसमें कुछ टाइप करता है? (डब्ल्यूपीएफ में)


@ John-myczek के code को बाध्य टेक्स्टबॉक्स के साथ उपयोग करते समय मैं थोड़ी कठिनाई में भाग गया। चूंकि टेक्स्टबॉक्स अपडेट होने पर फोकस ईवेंट नहीं बढ़ाता है, इसलिए वाटरमार्क नए टेक्स्ट के नीचे दिखाई देगा। इसे ठीक करने के लिए, मैंने बस एक और ईवेंट हैंडलर जोड़ा:

if (d is ComboBox || d is TextBox)
{
    control.GotKeyboardFocus += Control_GotKeyboardFocus;
    control.LostKeyboardFocus += Control_Loaded;

    if (d is TextBox)
        (d as TextBox).TextChanged += Control_TextChanged;
}


private static void Control_TextChanged(object sender, RoutedEventArgs e)
{
    var tb = (TextBox)sender;
    if (ShouldShowWatermark(tb))
    {
        ShowWatermark(tb);
    }
    else
    {
        RemoveWatermark(tb);
    }
}

आप एक वॉटरमार्क बना सकते हैं जिसे किसी संलग्न टेक्स्ट के साथ किसी भी टेक्स्टबॉक्स में जोड़ा जा सकता है। संलग्न संपत्ति का स्रोत यहां दिया गया है:

   using System;
   using System.Collections.Generic;
   using System.ComponentModel;
   using System.Windows;
   using System.Windows.Controls;
   using System.Windows.Controls.Primitives;
   using System.Windows.Documents;

   /// <summary>
   /// Class that provides the Watermark attached property
   /// </summary>
   public static class WatermarkService
   {
        /// <summary>
        /// Watermark Attached Dependency Property
        /// </summary>
        public static readonly DependencyProperty WatermarkProperty = DependencyProperty.RegisterAttached(
           "Watermark",
           typeof(object),
           typeof(WatermarkService),
           new FrameworkPropertyMetadata((object)null, new PropertyChangedCallback(OnWatermarkChanged)));

        #region Private Fields

        /// <summary>
        /// Dictionary of ItemsControls
        /// </summary>
        private static readonly Dictionary<object, ItemsControl> itemsControls = new Dictionary<object, ItemsControl>();

        #endregion

        /// <summary>
        /// Gets the Watermark property.  This dependency property indicates the watermark for the control.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> to get the property from</param>
        /// <returns>The value of the Watermark property</returns>
        public static object GetWatermark(DependencyObject d)
        {
            return (object)d.GetValue(WatermarkProperty);
        }

        /// <summary>
        /// Sets the Watermark property.  This dependency property indicates the watermark for the control.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> to set the property on</param>
        /// <param name="value">value of the property</param>
        public static void SetWatermark(DependencyObject d, object value)
        {
            d.SetValue(WatermarkProperty, value);
        }

        /// <summary>
        /// Handles changes to the Watermark property.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> that fired the event</param>
        /// <param name="e">A <see cref="DependencyPropertyChangedEventArgs"/> that contains the event data.</param>
        private static void OnWatermarkChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            Control control = (Control)d;
            control.Loaded += Control_Loaded;

            if (d is ComboBox)
            {
                control.GotKeyboardFocus += Control_GotKeyboardFocus;
                control.LostKeyboardFocus += Control_Loaded;
            }
            else if(d is TextBox)
            {
                control.GotKeyboardFocus += Control_GotKeyboardFocus;
                control.LostKeyboardFocus += Control_Loaded;
                ((TextBox)control).TextChanged += Control_GotKeyboardFocus;
            }

            if (d is ItemsControl && !(d is ComboBox))
            {
                ItemsControl i = (ItemsControl)d;

                // for Items property  
                i.ItemContainerGenerator.ItemsChanged += ItemsChanged;
                itemsControls.Add(i.ItemContainerGenerator, i);

                // for ItemsSource property  
                DependencyPropertyDescriptor prop = DependencyPropertyDescriptor.FromProperty(ItemsControl.ItemsSourceProperty, i.GetType());
                prop.AddValueChanged(i, ItemsSourceChanged);
            }
        }

        #region Event Handlers

        /// <summary>
        /// Handle the GotFocus event on the control
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private static void Control_GotKeyboardFocus(object sender, RoutedEventArgs e)
        {
            Control c = (Control)sender;
            if (ShouldShowWatermark(c))
            {
                ShowWatermark(c);
            }
            else
            {
                RemoveWatermark(c);
            }
        }

        /// <summary>
        /// Handle the Loaded and LostFocus event on the control
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private static void Control_Loaded(object sender, RoutedEventArgs e)
        {
            Control control = (Control)sender;
            if (ShouldShowWatermark(control))
            {
                ShowWatermark(control);
            }
        }

        /// <summary>
        /// Event handler for the items source changed event
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="EventArgs"/> that contains the event data.</param>
        private static void ItemsSourceChanged(object sender, EventArgs e)
        {
            ItemsControl c = (ItemsControl)sender;
            if (c.ItemsSource != null)
            {
                if (ShouldShowWatermark(c))
                {
                    ShowWatermark(c);
                }
                else
                {
                    RemoveWatermark(c);
                }
            }
            else
            {
                ShowWatermark(c);
            }
        }

        /// <summary>
        /// Event handler for the items changed event
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="ItemsChangedEventArgs"/> that contains the event data.</param>
        private static void ItemsChanged(object sender, ItemsChangedEventArgs e)
        {
            ItemsControl control;
            if (itemsControls.TryGetValue(sender, out control))
            {
                if (ShouldShowWatermark(control))
                {
                    ShowWatermark(control);
                }
                else
                {
                    RemoveWatermark(control);
                }
            }
        }

        #endregion

        #region Helper Methods

        /// <summary>
        /// Remove the watermark from the specified element
        /// </summary>
        /// <param name="control">Element to remove the watermark from</param>
        private static void RemoveWatermark(UIElement control)
        {
            AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);

            // layer could be null if control is no longer in the visual tree
            if (layer != null)
            {
                Adorner[] adorners = layer.GetAdorners(control);
                if (adorners == null)
                {
                    return;
                }

                foreach (Adorner adorner in adorners)
                {
                    if (adorner is WatermarkAdorner)
                    {
                        adorner.Visibility = Visibility.Hidden;
                        layer.Remove(adorner);
                    }
                }
            }
        }

        /// <summary>
        /// Show the watermark on the specified control
        /// </summary>
        /// <param name="control">Control to show the watermark on</param>
        private static void ShowWatermark(Control control)
        {
            AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);

            // layer could be null if control is no longer in the visual tree
            if (layer != null)
            {
                layer.Add(new WatermarkAdorner(control, GetWatermark(control)));
            }
        }

        /// <summary>
        /// Indicates whether or not the watermark should be shown on the specified control
        /// </summary>
        /// <param name="c"><see cref="Control"/> to test</param>
        /// <returns>true if the watermark should be shown; false otherwise</returns>
        private static bool ShouldShowWatermark(Control c)
        {
            if (c is ComboBox)
            {
                return (c as ComboBox).Text == string.Empty;
            }
            else if (c is TextBoxBase)
            {
                return (c as TextBox).Text == string.Empty;
            }
            else if (c is ItemsControl)
            {
                return (c as ItemsControl).Items.Count == 0;
            }
            else
            {
                return false;
            }
        }

        #endregion
    }

संलग्न संपत्ति वॉटरमार्कएडॉर्नर नामक एक कक्षा का उपयोग करती है, यहां वह स्रोत है:

   using System.Windows;
   using System.Windows.Controls;
   using System.Windows.Data;
   using System.Windows.Documents;
   using System.Windows.Media;

   /// <summary>
   /// Adorner for the watermark
   /// </summary>
   internal class WatermarkAdorner : Adorner
   {
      #region Private Fields

      /// <summary>
      /// <see cref="ContentPresenter"/> that holds the watermark
      /// </summary>
      private readonly ContentPresenter contentPresenter;

      #endregion

      #region Constructor

      /// <summary>
      /// Initializes a new instance of the <see cref="WatermarkAdorner"/> class
      /// </summary>
      /// <param name="adornedElement"><see cref="UIElement"/> to be adorned</param>
      /// <param name="watermark">The watermark</param>
      public WatermarkAdorner(UIElement adornedElement, object watermark) :
         base(adornedElement)
      {
         this.IsHitTestVisible = false;

         this.contentPresenter = new ContentPresenter();
         this.contentPresenter.Content = watermark;
         this.contentPresenter.Opacity = 0.5;
         this.contentPresenter.Margin = new Thickness(Control.Margin.Left + Control.Padding.Left, Control.Margin.Top + Control.Padding.Top, 0, 0);

         if (this.Control is ItemsControl && !(this.Control is ComboBox))
         {
            this.contentPresenter.VerticalAlignment = VerticalAlignment.Center;
            this.contentPresenter.HorizontalAlignment = HorizontalAlignment.Center;
         }

         // Hide the control adorner when the adorned element is hidden
         Binding binding = new Binding("IsVisible");
         binding.Source = adornedElement;
         binding.Converter = new BooleanToVisibilityConverter();
         this.SetBinding(VisibilityProperty, binding);
      }

      #endregion

      #region Protected Properties

      /// <summary>
      /// Gets the number of children for the <see cref="ContainerVisual"/>.
      /// </summary>
      protected override int VisualChildrenCount
      {
         get { return 1; }
      }

      #endregion

      #region Private Properties

      /// <summary>
      /// Gets the control that is being adorned
      /// </summary>
      private Control Control
      {
         get { return (Control)this.AdornedElement; }
      }

      #endregion

      #region Protected Overrides

      /// <summary>
      /// Returns a specified child <see cref="Visual"/> for the parent <see cref="ContainerVisual"/>.
      /// </summary>
      /// <param name="index">A 32-bit signed integer that represents the index value of the child <see cref="Visual"/>. The value of index must be between 0 and <see cref="VisualChildrenCount"/> - 1.</param>
      /// <returns>The child <see cref="Visual"/>.</returns>
      protected override Visual GetVisualChild(int index)
      {
         return this.contentPresenter;
      }

      /// <summary>
      /// Implements any custom measuring behavior for the adorner.
      /// </summary>
      /// <param name="constraint">A size to constrain the adorner to.</param>
      /// <returns>A <see cref="Size"/> object representing the amount of layout space needed by the adorner.</returns>
      protected override Size MeasureOverride(Size constraint)
      {
         // Here's the secret to getting the adorner to cover the whole control
         this.contentPresenter.Measure(Control.RenderSize);
         return Control.RenderSize;
      }

      /// <summary>
      /// When overridden in a derived class, positions child elements and determines a size for a <see cref="FrameworkElement"/> derived class. 
      /// </summary>
      /// <param name="finalSize">The final area within the parent that this element should use to arrange itself and its children.</param>
      /// <returns>The actual size used.</returns>
      protected override Size ArrangeOverride(Size finalSize)
      {
         this.contentPresenter.Arrange(new Rect(finalSize));
         return finalSize;
      }

      #endregion
   }

अब आप इस तरह किसी भी टेक्स्टबॉक्स पर वॉटरमार्क डाल सकते हैं:

<AdornerDecorator>
   <TextBox x:Name="SearchTextBox">
      <controls:WatermarkService.Watermark>
         <TextBlock>Type here to search text</TextBlock>
      </controls:WatermarkService.Watermark>
   </TextBox>
</AdornerDecorator>

वॉटरमार्क कुछ भी हो सकता है जो आप चाहते हैं (पाठ, छवियां ...)। टेक्स्टबॉक्स के लिए काम करने के अलावा, यह वॉटरमार्क कॉम्बोबॉक्स और आइटमकंट्रोल के लिए भी काम करता है।

इस कोड को इस ब्लॉग पोस्ट से अनुकूलित किया गया था।


डेविड ओवेन्स का यहां एक पूर्ण "खोज बॉक्स" का एक अधिक जटिल उदाहरण here



मैंने जॉन मायकेज़ के समाधान को देखा, और कॉम्बोबॉक्स और पासवर्डबॉक्स के लिए संगतता के बारे में इसकी टिप्पणियां देखीं, इसलिए मैंने जॉन मायकेज़ के समाधान में सुधार किया, और यहां यह है:

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Controls.Primitives;
    using System.Windows.Documents;



        /// <summary>
        /// Class that provides the Watermark attached property
        /// </summary>
    public static class WatermarkService
    {
        /// <summary>
        /// Watermark Attached Dependency Property
        /// </summary>
        public static readonly DependencyProperty WatermarkProperty = DependencyProperty.RegisterAttached(
           "Watermark",
           typeof(object),
           typeof(WatermarkService),
           new FrameworkPropertyMetadata((object)null, new PropertyChangedCallback(OnWatermarkChanged)));

        #region Private Fields

        /// <summary>
        /// Dictionary of ItemsControls
        /// </summary>
        private static readonly Dictionary<object, ItemsControl> itemsControls = new Dictionary<object, ItemsControl>();

        #endregion

        /// <summary>
        /// Gets the Watermark property.  This dependency property indicates the watermark for the control.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> to get the property from</param>
        /// <returns>The value of the Watermark property</returns>
        public static object GetWatermark(DependencyObject d)
        {
            return (object)d.GetValue(WatermarkProperty);
        }

        /// <summary>
        /// Sets the Watermark property.  This dependency property indicates the watermark for the control.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> to set the property on</param>
        /// <param name="value">value of the property</param>
        public static void SetWatermark(DependencyObject d, object value)
        {
            d.SetValue(WatermarkProperty, value);
        }

        /// <summary>
        /// Handles changes to the Watermark property.
        /// </summary>
        /// <param name="d"><see cref="DependencyObject"/> that fired the event</param>
        /// <param name="e">A <see cref="DependencyPropertyChangedEventArgs"/> that contains the event data.</param>
        private static void OnWatermarkChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            Control control = (Control)d;
            control.Loaded += Control_Loaded;

            if (d is TextBox || d is PasswordBox)
            {
                control.GotKeyboardFocus += Control_GotKeyboardFocus;
                control.LostKeyboardFocus += Control_Loaded;
            }
            else if (d is ComboBox)
            {
                control.GotKeyboardFocus += Control_GotKeyboardFocus;
                control.LostKeyboardFocus += Control_Loaded;
                (d as ComboBox).SelectionChanged += new SelectionChangedEventHandler(SelectionChanged);
            }
            else if (d is ItemsControl)
            {
                ItemsControl i = (ItemsControl)d;

                // for Items property  
                i.ItemContainerGenerator.ItemsChanged += ItemsChanged;
                itemsControls.Add(i.ItemContainerGenerator, i);

                // for ItemsSource property  
                DependencyPropertyDescriptor prop = DependencyPropertyDescriptor.FromProperty(ItemsControl.ItemsSourceProperty, i.GetType());
                prop.AddValueChanged(i, ItemsSourceChanged);
            }
        }

        /// <summary>
        /// Event handler for the selection changed event
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="ItemsChangedEventArgs"/> that contains the event data.</param>
        private static void SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            Control control = (Control)sender;
            if (ShouldShowWatermark(control))
            {
                ShowWatermark(control);
            }
            else
            {
                RemoveWatermark(control);
            }
        }

        #region Event Handlers

        /// <summary>
        /// Handle the GotFocus event on the control
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private static void Control_GotKeyboardFocus(object sender, RoutedEventArgs e)
        {
            Control c = (Control)sender;
            if (ShouldShowWatermark(c))
            {
                RemoveWatermark(c);
            }
        }

        /// <summary>
        /// Handle the Loaded and LostFocus event on the control
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private static void Control_Loaded(object sender, RoutedEventArgs e)
        {
            Control control = (Control)sender;
            if (ShouldShowWatermark(control))
            {
                ShowWatermark(control);
            }
        }

        /// <summary>
        /// Event handler for the items source changed event
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="EventArgs"/> that contains the event data.</param>
        private static void ItemsSourceChanged(object sender, EventArgs e)
        {
            ItemsControl c = (ItemsControl)sender;
            if (c.ItemsSource != null)
            {
                if (ShouldShowWatermark(c))
                {
                    ShowWatermark(c);
                }
                else
                {
                    RemoveWatermark(c);
                }
            }
            else
            {
                ShowWatermark(c);
            }
        }

        /// <summary>
        /// Event handler for the items changed event
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">A <see cref="ItemsChangedEventArgs"/> that contains the event data.</param>
        private static void ItemsChanged(object sender, ItemsChangedEventArgs e)
        {
            ItemsControl control;
            if (itemsControls.TryGetValue(sender, out control))
            {
                if (ShouldShowWatermark(control))
                {
                    ShowWatermark(control);
                }
                else
                {
                    RemoveWatermark(control);
                }
            }
        }

        #endregion

        #region Helper Methods

        /// <summary>
        /// Remove the watermark from the specified element
        /// </summary>
        /// <param name="control">Element to remove the watermark from</param>
        private static void RemoveWatermark(UIElement control)
        {
            AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);

            // layer could be null if control is no longer in the visual tree
            if (layer != null)
            {
                Adorner[] adorners = layer.GetAdorners(control);
                if (adorners == null)
                {
                    return;
                }

                foreach (Adorner adorner in adorners)
                {
                    if (adorner is WatermarkAdorner)
                    {
                        adorner.Visibility = Visibility.Hidden;
                        layer.Remove(adorner);
                    }
                }
            }
        }

        /// <summary>
        /// Show the watermark on the specified control
        /// </summary>
        /// <param name="control">Control to show the watermark on</param>
        private static void ShowWatermark(Control control)
        {
            AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);

            // layer could be null if control is no longer in the visual tree
            if (layer != null)
            {
                layer.Add(new WatermarkAdorner(control, GetWatermark(control)));
            }
        }

        /// <summary>
        /// Indicates whether or not the watermark should be shown on the specified control
        /// </summary>
        /// <param name="c"><see cref="Control"/> to test</param>
        /// <returns>true if the watermark should be shown; false otherwise</returns>
        private static bool ShouldShowWatermark(Control c)
        {
            if (c is ComboBox)
            {
                return (c as ComboBox).SelectedItem == null;
                //return (c as ComboBox).Text == string.Empty;
            }
            else if (c is TextBoxBase)
            {
                return (c as TextBox).Text == string.Empty;
            }
            else if (c is PasswordBox)
            {
                return (c as PasswordBox).Password == string.Empty;
            }
            else if (c is ItemsControl)
            {
                return (c as ItemsControl).Items.Count == 0;
            }
            else
            {
                return false;
            }
        }

        #endregion
    }

अब, कॉम्बोबॉक्स भी संपादन योग्य हो सकता है, और पासवर्डबॉक्स भी वॉटरमार्क जोड़ सकता है। मार्जिन समस्या को हल करने के लिए ऊपर JoanComasFdz की टिप्पणी का उपयोग करना न भूलें।

और, ज़ाहिर है, सभी क्रेडिट जॉन मायकेज़ के पास जाता है।



यह एक नमूना है जो दर्शाता है कि डब्ल्यूपीएफ में वॉटरमार्क टेक्स्टबॉक्स कैसे बनाया जाए:

<Window x:Class="WaterMarkTextBoxDemo.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WaterMarkTextBoxDemo"
    Height="200" Width="400">

    <Window.Resources>

        <SolidColorBrush x:Key="brushWatermarkBackground" Color="White" />
        <SolidColorBrush x:Key="brushWatermarkForeground" Color="LightSteelBlue" />
        <SolidColorBrush x:Key="brushWatermarkBorder" Color="Indigo" />

        <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
        <local:TextInputToVisibilityConverter x:Key="TextInputToVisibilityConverter" />

        <Style x:Key="EntryFieldStyle" TargetType="Grid" >
            <Setter Property="HorizontalAlignment" Value="Stretch" />
            <Setter Property="VerticalAlignment" Value="Center" />
            <Setter Property="Margin" Value="20,0" />
        </Style>

    </Window.Resources>


    <Grid Background="LightBlue">

        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition />
            <RowDefinition />
        </Grid.RowDefinitions>

        <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>

        <Grid Grid.Row="1" Background="{StaticResource brushWatermarkBackground}" Style="{StaticResource EntryFieldStyle}" >
            <TextBlock Margin="5,2" Text="This dissappears as the control gets focus..." Foreground="{StaticResource brushWatermarkForeground}" >
                <TextBlock.Visibility>
                    <MultiBinding Converter="{StaticResource TextInputToVisibilityConverter}">
                        <Binding ElementName="txtUserEntry2" Path="Text.IsEmpty" />
                        <Binding ElementName="txtUserEntry2" Path="IsFocused" />
                    </MultiBinding>
                </TextBlock.Visibility>
            </TextBlock>
            <TextBox Name="txtUserEntry2" Background="Transparent" BorderBrush="{StaticResource brushWatermarkBorder}" />
        </Grid>

    </Grid>

</Window>

TextInputToVisibilityConverter को इस प्रकार परिभाषित किया गया है:

using System;
using System.Windows.Data;
using System.Windows;

namespace WaterMarkTextBoxDemo
{
    public class TextInputToVisibilityConverter : IMultiValueConverter
    {
        public object Convert( object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture )
        {
            // Always test MultiValueConverter inputs for non-null
            // (to avoid crash bugs for views in the designer)
            if (values[0] is bool && values[1] is bool)
            {
                bool hasText = !(bool)values[0];
                bool hasFocus = (bool)values[1];

                if (hasFocus || hasText)
                    return Visibility.Collapsed;
            }

            return Visibility.Visible;
        }


        public object[] ConvertBack( object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture )
        {
            throw new NotImplementedException();
        }
    }
}

नोट: यह मेरा कोड नहीं है। मैंने इसे here पाया, लेकिन मुझे लगता है कि यह सबसे अच्छा तरीका है।


कोडप्रोजेक्ट पर "XAML की 3 पंक्तियों" में इसे कैसे करें, इस पर एक लेख है

<Grid Background="{StaticResource brushWatermarkBackground}">
  <TextBlock Margin="5,2" Text="Type something..."
             Foreground="{StaticResource brushForeground}"
             Visibility="{Binding ElementName=txtUserEntry, Path=Text.IsEmpty,
                          Converter={StaticResource BooleanToVisibilityConverter}}" />
  <TextBox Name="txtUserEntry" Background="Transparent"
           BorderBrush="{StaticResource brushBorder}" />
</Grid>

ठीक है, ठीक है यह XAML प्रारूपित 3 लाइन नहीं हो सकता है, लेकिन यह बहुत आसान है।

हालांकि, ध्यान देने योग्य एक बात यह है कि यह टेक्स्ट संपत्ति पर एक गैर मानक विस्तार विधि का उपयोग करता है, जिसे "IsEmpty" कहा जाता है। आपको इसे स्वयं लागू करने की आवश्यकता है, हालांकि लेख में इसका उल्लेख नहीं है।


इस पुस्तकालय में वॉटरमार्क है।

Nuget पैकेज

नमूना उपयोग:

<TextBox adorners:Watermark.Text="Write something here" 
         adorners:Watermark.TextStyle="{StaticResource AdornerTextStyle}"
         adorners:Watermark.VisibleWhen="EmptyAndNotKeyboardFocused"/>

I decided to solve this via a Behavior. It uses a Hint property to define the text to display (could also be an object, if you prefer) and a Value property to evaluate wether the hint should be visible or not.

The Behavior is declared as follows:

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Interactivity;
using System.Windows.Media;

    public class HintBehavior : Behavior<ContentControl>
    {
        public static readonly DependencyProperty HintProperty = DependencyProperty
            .Register("Hint", typeof (string), typeof (HintBehavior)
            //, new FrameworkPropertyMetadata(null, OnHintChanged)
            );

        public string Hint
        {
            get { return (string) GetValue(HintProperty); }
            set { SetValue(HintProperty, value); }
        }

        public static readonly DependencyProperty ValueProperty = DependencyProperty
            .Register("Value", typeof (object), typeof (HintBehavior)
                , new FrameworkPropertyMetadata(null, OnValueChanged));

        private static void OnValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var visible = e.NewValue == null;
            d.SetValue(VisibilityProperty, visible ? Visibility.Visible : Visibility.Collapsed);
        }

        public object Value
        {
            get { return GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        public static readonly DependencyProperty VisibilityProperty = DependencyProperty
            .Register("Visibility", typeof (Visibility), typeof (HintBehavior)
                , new FrameworkPropertyMetadata(Visibility.Visible
                    //, new PropertyChangedCallback(OnVisibilityChanged)
                    ));

        public Visibility Visibility
        {
            get { return (Visibility) GetValue(VisibilityProperty); }
            set { SetValue(VisibilityProperty, value); }
        }

        public static readonly DependencyProperty ForegroundProperty = DependencyProperty
            .Register("Foreground", typeof (Brush), typeof (HintBehavior)
                , new FrameworkPropertyMetadata(new SolidColorBrush(Colors.DarkGray)
                    //, new PropertyChangedCallback(OnForegroundChanged)
                    ));

        public Brush Foreground
        {
            get { return (Brush) GetValue(ForegroundProperty); }
            set { SetValue(ForegroundProperty, value); }
        }

        public static readonly DependencyProperty MarginProperty = DependencyProperty
            .Register("Margin", typeof (Thickness), typeof (HintBehavior)
                , new FrameworkPropertyMetadata(new Thickness(4, 5, 0, 0)
                    //, new PropertyChangedCallback(OnMarginChanged)
                    ));

        public Thickness Margin
        {
            get { return (Thickness) GetValue(MarginProperty); }
            set { SetValue(MarginProperty, value); }
        }


        private static ResourceDictionary _hintBehaviorResources;

        public static ResourceDictionary HintBehaviorResources
        {
            get
            {
                if (_hintBehaviorResources == null)
                {
                    var res = new ResourceDictionary
                    {
                        Source = new Uri("/Mayflower.Client.Core;component/Behaviors/HintBehaviorResources.xaml",
                            UriKind.RelativeOrAbsolute)
                    };
                    _hintBehaviorResources = res;
                }
                return _hintBehaviorResources;
            }
        }


        protected override void OnAttached()
        {
            base.OnAttached();
            var t = (ControlTemplate) HintBehaviorResources["HintBehaviorWrapper"];
            AssociatedObject.Template = t;
            AssociatedObject.Loaded += OnLoaded;
        }

        private void OnLoaded(object sender, RoutedEventArgs e)
        {
            AssociatedObject.Loaded -= OnLoaded;
            var label = (Label) AssociatedObject.Template.FindName("PART_HintLabel", AssociatedObject);
            label.DataContext = this;
            //label.Content = "Hello...";
            label.SetBinding(UIElement.VisibilityProperty, new Binding("Visibility") {Source = this, Mode = BindingMode.OneWay});
            label.SetBinding(ContentControl.ContentProperty, new Binding("Hint") {Source = this, Mode = BindingMode.OneWay});
            label.SetBinding(Control.ForegroundProperty, new Binding("Foreground") {Source = this, Mode = BindingMode.OneWay});
            label.SetBinding(FrameworkElement.MarginProperty, new Binding("Margin") {Source = this, Mode = BindingMode.OneWay});
        }
    }

It wraps the target with it's own template, adding to it a label:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <ControlTemplate x:Key="HintBehaviorWrapper" TargetType="{x:Type ContentControl}">
        <Grid>
            <ContentPresenter Content="{TemplateBinding Content}" />
            <Label x:Name="PART_HintLabel" IsHitTestVisible="False" Padding="0" />
        </Grid>
    </ControlTemplate>
</ResourceDictionary>

To use it, just add it as a behavior and bind your values (in my case I add it in a ControlTemplate, hence the binding):

<ContentControl>
    <i:Interaction.Behaviors>
        <behaviors:HintBehavior Value="{Binding Property, RelativeSource={RelativeSource TemplatedParent}}"
                                                        Hint="{Binding Hint, RelativeSource={RelativeSource TemplatedParent}}" />
    </i:Interaction.Behaviors>
    <TextBox ... />
</ContentControl>

I would love feedback if this is considered a clean solution. It does not require static dictionaries and hence has no memory leak.


I found this way to do it in a very fast and easy way

<ComboBox x:Name="comboBox1" SelectedIndex="0" HorizontalAlignment="Left" Margin="202,43,0,0" VerticalAlignment="Top" Width="149">
  <ComboBoxItem Visibility="Collapsed">
    <TextBlock Foreground="Gray" FontStyle="Italic">Please select ...</TextBlock>
  </ComboBoxItem>
  <ComboBoxItem Name="cbiFirst1">First Item</ComboBoxItem>
  <ComboBoxItem Name="cbiSecond1">Second Item</ComboBoxItem>
  <ComboBoxItem Name="cbiThird1">third Item</ComboBoxItem>
</ComboBox>

Maybe it can help to anyone trying to do this

Source: http://www.admindiaries.com/displaying-a-please-select-watermark-type-text-in-a-wpf-combobox/


My solution is quite simple.

In my login window. the xaml is like this.

 <DockPanel HorizontalAlignment="Center" VerticalAlignment="Center" Height="80" Width="300" LastChildFill="True">
        <Button Margin="5,0,0,0" Click="login_Click" DockPanel.Dock="Right"  VerticalAlignment="Center" ToolTip="Login to system">
            Login
        </Button>
        <StackPanel>
            <TextBox x:Name="userNameWatermarked" Height="25" Foreground="Gray" Text="UserName" GotFocus="userNameWatermarked_GotFocus"></TextBox>
            <TextBox x:Name="userName" Height="25"  TextChanged="loginElement_TextChanged" Visibility="Collapsed" LostFocus="userName_LostFocus" ></TextBox>
            <TextBox x:Name="passwordWatermarked" Height="25" Foreground="Gray" Text="Password"  Margin="0,5,0,5" GotFocus="passwordWatermarked_GotFocus"></TextBox>
            <PasswordBox x:Name="password" Height="25" PasswordChanged="password_PasswordChanged" KeyUp="password_KeyUp" LostFocus="password_LostFocus" Margin="0,5,0,5" Visibility="Collapsed"></PasswordBox>
            <TextBlock x:Name="loginError" Visibility="Hidden" Foreground="Red" FontSize="12"></TextBlock>
        </StackPanel>
    </DockPanel>

the code is like this.

private void userNameWatermarked_GotFocus(object sender, RoutedEventArgs e)
    {
        userNameWatermarked.Visibility = System.Windows.Visibility.Collapsed;
        userName.Visibility = System.Windows.Visibility.Visible;
        userName.Focus();
    }

    private void userName_LostFocus(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(this.userName.Text))
        {
            userName.Visibility = System.Windows.Visibility.Collapsed;
            userNameWatermarked.Visibility = System.Windows.Visibility.Visible;
        }
    }

    private void passwordWatermarked_GotFocus(object sender, RoutedEventArgs e)
    {
        passwordWatermarked.Visibility = System.Windows.Visibility.Collapsed;
        password.Visibility = System.Windows.Visibility.Visible;
        password.Focus();
    }

    private void password_LostFocus(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(this.password.Password))
        {
            password.Visibility = System.Windows.Visibility.Collapsed;
            passwordWatermarked.Visibility = System.Windows.Visibility.Visible;
        }
    }

Just decide to hide or show the watermark textbox is enough. Though not beautiful,but work well.


Set up the text box with placeholder text in a soft color...

public MainWindow ( )
{
    InitializeComponent ( );
    txtInput.Text = "Type something here...";
    txtInput.Foreground = Brushes.DimGray;
}

When the text box gets the focus, clear it and change the text color

private void txtInput_GotFocus ( object sender, EventArgs e )
{
    MessageBox.Show ( "got focus" );
    txtInput.Text = "";
    txtInput.Foreground = Brushes.Red;
}

Well here is mine: not necessarily the best, but as it is simple it is easy to edit to your taste.

<UserControl x:Class="WPFControls.ShadowedTextBox"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WPFControls"
    Name="Root">
<UserControl.Resources>
    <local:ShadowConverter x:Key="ShadowConvert"/>
</UserControl.Resources>
<Grid>
    <TextBox Name="textBox" 
             Foreground="{Binding ElementName=Root, Path=Foreground}"
             Text="{Binding ElementName=Root, Path=Text, UpdateSourceTrigger=PropertyChanged}"
             TextChanged="textBox_TextChanged"
             TextWrapping="Wrap"
             VerticalContentAlignment="Center"/>
    <TextBlock Name="WaterMarkLabel"
           IsHitTestVisible="False"
           Foreground="{Binding ElementName=Root,Path=Foreground}"
           FontWeight="Thin"
           Opacity=".345"
           FontStyle="Italic"
           Text="{Binding ElementName=Root, Path=Watermark}"
           VerticalAlignment="Center"
           TextWrapping="Wrap"
           TextAlignment="Center">
        <TextBlock.Visibility>
            <MultiBinding Converter="{StaticResource ShadowConvert}">
                <Binding ElementName="textBox" Path="Text"/>
            </MultiBinding>
        </TextBlock.Visibility> 
    </TextBlock>
</Grid>

The converter, as it is written now it is not necessary that it is a MultiConverter, but in this wasy it can be extended easily

using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;

namespace WPFControls
{
    class ShadowConverter:IMultiValueConverter
    {
        #region Implementation of IMultiValueConverter

        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            var text = (string) values[0];
            return text == string.Empty
                       ? Visibility.Visible
                       : Visibility.Collapsed;
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            return new object[0];
        }

        #endregion
    }
}

and finally the code behind:

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

namespace WPFControls
{
    /// <summary>
    /// Interaction logic for ShadowedTextBox.xaml
    /// </summary>
    public partial class ShadowedTextBox : UserControl
    {
        public event TextChangedEventHandler TextChanged;

        public ShadowedTextBox()
        {
            InitializeComponent();
        }

        public static readonly DependencyProperty WatermarkProperty =
            DependencyProperty.Register("Watermark",
                                        typeof (string),
                                        typeof (ShadowedTextBox),
                                        new UIPropertyMetadata(string.Empty));

        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register("Text",
                                        typeof (string),
                                        typeof (ShadowedTextBox),
                                        new UIPropertyMetadata(string.Empty));

        public static readonly DependencyProperty TextChangedProperty =
            DependencyProperty.Register("TextChanged",
                                        typeof (TextChangedEventHandler),
                                        typeof (ShadowedTextBox),
                                        new UIPropertyMetadata(null));

        public string Watermark
        {
            get { return (string)GetValue(WatermarkProperty); }
            set
            {
                SetValue(WatermarkProperty, value);
            }
        }

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

        private void textBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            if (TextChanged != null) TextChanged(this, e);
        }

        public void Clear()
        {
            textBox.Clear();
        }

    }
}

You can keep a seperate value for the entered text and you can set it along with the "Text" field of the text box in the "GotFocus" and "LostFocus" events. When you get the focus, you'll want to clear the text box if there is no value. And when you loss the focus, you'll want to set the get the "Text" value from the text box and then reset the "Text" value of the text box to the place holder if it is empty.

private String username = "";

private void usernameTextBox_GotFocus(object sender, RoutedEventArgs e) {
  if (String.IsNullOrEmpty(username)) {
    usernameTextBox.Text = "";
  }
}

private void usernameTextBox_LostFocus(object sender, RoutedEventArgs e) {
  username = usernameTextBox.Text;
  if (String.IsNullOrEmpty(usernameTextBox.Text)) {
    usernameTextBox.Text = "Username";
  }
}

Then you just have to make sure that the "Text" value of the text box is initialized to the place holder text.

<TextBox x:Name="usernameTextBox" Text="Username" GotFocus="usernameTextBox_GotFocus" LostFocus="usernameTextBox_LostFocus" />

You can further extract this into a class that extends the "TextBox" class and then reuse it through out your project.

namespace UI {
  public class PlaceholderTextBox : TextBox {
    public String Value { get; set; }
    public String PlaceholderText { get; set; }
    public Brush PlaceholderBrush { get; set; }
    private Brush ValuedBrush { get; set; }

    public PlaceholderTextBox() : base() {}

    protected override void OnInitialized(EventArgs e) {
      base.OnInitialized(e);

      ValuedBrush = this.Foreground;

      if (String.IsNullOrEmpty(this.Text)) {
        this.Text = PlaceholderText;
        this.Foreground = PlaceholderBrush;
      }
    }

    protected override void OnGotFocus(System.Windows.RoutedEventArgs e) {
      this.Foreground = ValuedBrush;
      if (String.IsNullOrEmpty(Value)) {
        this.Text = "";
      }

      base.OnGotFocus(e);
    }

    protected override void OnLostFocus(System.Windows.RoutedEventArgs e) {
      Value = this.Text;
      if (String.IsNullOrEmpty(this.Text)) {
        this.Text = PlaceholderText;
        this.Foreground = PlaceholderBrush;
      }

      base.OnLostFocus(e);
    }
  }
}

And then this can be added in the directly in the xaml.

<Window x:Class="UI.LoginWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:m="clr-namespace:UI"
        Initialized="Window_Initialized">
    <Grid>
        <m:PlaceholderTextBox x:Name="usernameTextBox" PlaceholderText="Username" PlaceholderBrush="Gray" />
    </Grid>
</Window>

you can use GetFocus() and LostFocus() events to do this

here is the example:

    private void txtData1_GetFocus(object sender, RoutedEventArgs e)
    {
        if (txtData1.Text == "TextBox1abc")
        {
            txtData1.Text = string.Empty;
        }
    }

    private void txtData1_LostFocus(object sender, RoutedEventArgs e)
    {
        if (txtData1.Text == string.Empty)
        {
            txtData1.Text = "TextBox1abc";
        }
    }

<TextBox    Grid.Column="0" Name="TextBox_SearchBar" AcceptsReturn="False" AcceptsTab="False" TextWrapping="Wrap" KeyUp="TextBox_SearchBar_KeyUp" />
<TextBox    Grid.Column="0" Name="TextBox_Watermark" Text="Search Test Sets" Foreground="Gray" GotFocus="TextBox_Watermark_GotFocus" />

private void TextBox_Watermark_GotFocus( object sender, RoutedEventArgs e ) {
    TextBox_Watermark.Visibility = Visibility.Hidden;
    TextBox_SearchBar.Focus();
}

<TextBox x:Name="OrderTxt" HorizontalAlignment="Left" VerticalAlignment="Top" VerticalContentAlignment="Center" Margin="10,10,0,0" Width="188" Height="32"/>

<Label IsHitTestVisible="False" Content="Order number" DataContext="{Binding ElementName=OrderTxt}" Foreground="DarkGray">
    <Label.Style>
        <Style TargetType="{x:Type Label}">
            <Setter Property="Visibility" Value="Collapsed"/>
            <Setter Property="Width" Value="{Binding Width}"/>
            <Setter Property="Height" Value="{Binding Height}"/>
            <Setter Property="Margin" Value="{Binding Margin}"/>
            <Setter Property="VerticalAlignment" Value="{Binding VerticalAlignment}"/>
            <Setter Property="HorizontalAlignment" Value="{Binding HorizontalAlignment}"/>
            <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment}"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding Text}" Value="">
                    <Setter Property="Visibility" Value="Visible"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Label.Style>
</Label>

<Window.Resources>

    <Style x:Key="TextBoxUserStyle" BasedOn="{x:Null}" TargetType="{x:Type TextBox}">
      <Setter Property="Foreground" Value="Black"/>
      <Setter Property="HorizontalAlignment" Value="Center"/>
      <Setter Property="VerticalContentAlignment" Value="Center"/>
      <Setter Property="Width" Value="225"/>
      <Setter Property="Height" Value="25"/>
      <Setter Property="FontSize" Value="12"/>
      <Setter Property="Padding" Value="1"/>
      <Setter Property="Margin" Value="5"/>
      <Setter Property="AllowDrop" Value="true"/>
      <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="{x:Type TextBox}">
            <Border x:Name="OuterBorder" BorderBrush="#5AFFFFFF" BorderThickness="1,1,1,1" CornerRadius="4,4,4,4">
              <Border x:Name="InnerBorder" Background="#FFFFFFFF" BorderBrush="#33000000" BorderThickness="1,1,1,1" CornerRadius="3,3,3,3">
                <ScrollViewer SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" x:Name="PART_ContentHost"/>
              </Border>
            </Border>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>

    <Style x:Key="PasswordBoxVistaStyle" BasedOn="{x:Null}" TargetType="{x:Type PasswordBox}">
      <Setter Property="Foreground" Value="Black"/>
      <Setter Property="HorizontalAlignment" Value="Center"/>
      <Setter Property="VerticalContentAlignment" Value="Center"/>
      <Setter Property="Width" Value="225"/>
      <Setter Property="Height" Value="25"/>
      <Setter Property="FontSize" Value="12"/>
      <Setter Property="Padding" Value="1"/>
      <Setter Property="Margin" Value="5"/>
      <Setter Property="AllowDrop" Value="true"/>
      <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="{x:Type PasswordBox}">
            <Border x:Name="OuterBorder" BorderBrush="#5AFFFFFF" BorderThickness="1,1,1,1" CornerRadius="4,4,4,4">
              <Border x:Name="InnerBorder" Background="#FFFFFFFF" BorderBrush="#33000000" BorderThickness="1,1,1,1" CornerRadius="3,3,3,3">
                <Grid>
                  <Label x:Name="lblPwd" Content="Password" FontSize="11" VerticalAlignment="Center" Margin="2,0,0,0" FontFamily="Verdana" Foreground="#828385" Padding="0"/>
                  <ScrollViewer SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" x:Name="PART_ContentHost"/>
                </Grid>
              </Border>
            </Border>
            <ControlTemplate.Triggers>
              <Trigger Property="IsFocused" Value="True">
                <Setter Property="Visibility" TargetName="lblPwd" Value="Hidden"/>
              </Trigger>
            </ControlTemplate.Triggers>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </Window.Resources>


        <PasswordBox Style="{StaticResource PasswordBoxVistaStyle}" Margin="169,143,22,0" Name="txtPassword" FontSize="14" TabIndex="2" Height="31" VerticalAlignment="Top" />

This can help check it with your code.When applied to password box,it will show Password,which will disappear when usertypes.







hint