[Attached Property] WPF TextBox clears Text when user presses Escape key

To add the behavior to the WPF TextBox, use the following XAML.

<Window x:Class="WPF.MainWindow" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
        Title="WPF TextBox MVVM DataBinding Example" Height="500" Width="500"
         xmlns:Behaviors="clr-namespace:Behaviors">
    <Grid>
        <TextBox Behaviors:TextBoxBehavior.EscapeClearsText="True" />
    >
>


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

namespace  Behaviors
{
    public class TextBoxBehavior
    {
        #region Attached Property EscapeClearsText

        public static readonly DependencyProperty EscapeClearsTextProperty
           = DependencyProperty.RegisterAttached("EscapeClearsText", typeof(bool), typeof(TextBoxBehavior),
                new FrameworkPropertyMetadata(false, new PropertyChangedCallback(OnEscapeClearsTextChanged)));

        private static void OnEscapeClearsTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if ((bool)e.NewValue)
            {
                var textBox = d as TextBox;
                if (textBox != null)
                {
                    textBox.KeyUp -= TextBoxKeyUp;
                    textBox.KeyUp += TextBoxKeyUp;
                }
            }
        }

        private static void TextBoxKeyUp(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Escape)
            {
                ((TextBox) sender).Text = string.Empty;
            }
        }

        public static void SetEscapeClearsText(DependencyObject dependencyObject, bool escapeClearsText)
        {
            if (!ReferenceEquals(null, dependencyObject))
                dependencyObject.SetValue(EscapeClearsTextProperty, escapeClearsText);
        }

        public static bool GetEscapeClearsText(DependencyObject dependencyObject)
        {
            if (!ReferenceEquals(null, dependencyObject))
                return (bool)dependencyObject.GetValue(EscapeClearsTextProperty);
            return false;
        }

        #endregion Attached Property EscapeClearsText
    }
}

Comments

Post a Comment

Popular posts from this blog

WPF How to Dispose ViewModel when the associated UserControl (Not Window) closes?

Note: If your WPF UserControl is hosted in MFC Window, you may want to clean-up the ViewModel that is DataContext of your UserControl. Since Unloaded event is not called reliably for the UserControl when the hosting MFC Window closes, there is a need for another solution. XAML: < UserControl  x : Class = "Views.MyUserControl"               xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"               xmlns : x = "http://schemas.microsoft.com/winfx/2006/xaml"               xmlns : mc = "http://schemas.openxmlformats.org/markup-compatibility/2006"                 xmlns : d = "http://schemas.microsoft.com/expression/blend/2008"                 mc : Ignorable = "d"                 d : DesignHeight = "300"  d : DesignWidth = "300" >      < Grid >                   </ Grid > </ UserControl > Code Behind: using  System; using  ViewModels; name
Read more

C# How to unit test Dispatcher

Dispatcher provides services for managing the queue of work items for a thread. Sometimes to execute a task on a background thread.  Any task executed by calling Dispatcher.BeginInvoke(...) in unit test does not get executed until you do some wire-up. This is how you would unit test code with Dispatcher. using  System; using  System.Windows.Threading; using  Microsoft.VisualStudio.TestTools.UnitTesting; namespace  UnitTesting.Tests {     [ TestClass ]      public   class   DispatcherUtilTest     {          private   ClassThatUsesDispatcher  _subject;         [ TestInitialize ]          public   void  TestInitialize()         {             _subject =  new   ClassThatUsesDispatcher ();         }         [ TestMethod ]          public   void  UseDispatcher()         {              // Arrange              var  backgroundWorkDone =  false ;             _subject.BackgroungWorkAction = () => { backgroundWorkDone =  true ; };              // Act             _subject.DoWork(
Read more

WPF: How to Deep Copy WPF object (e.g. UIElement) ?

         ///  Generic Method to perform Deep-Copy of a WPF element (e.g. UIElement)          public   static  T DeepCopy (T element)         {              var  xaml =  XamlWriter .Save(element);              var  xamlString =  new   StringReader (xaml);              var  xmlTextReader =  new   XmlTextReader (xamlString);              var  deepCopyObject = (T) XamlReader .Load(xmlTextReader);              return  deepCopyObject;         }          ///  Test showing that the deep copied object does not have the same reference as the object being copied         [ TestMethod ]          public   void  DeepCopy()         {              // Arrange              Shape  shape =  new   Rectangle  {Fill =  new   SolidColorBrush ( Colors .Red)};              // Act              var  deepCopyShape =  MyClass .DeepCopy(shape);              // Assert              Assert .AreNotSame(shape, deepCopyShape);         }  
Read more