Wie erkennt man eine Änderung in der Eigenschaft Text eines TextBlocks?

Question

Gibt es eine Möglichkeit, eine Änderung in der Text-Eigenschaft eines TextBlock-Elements mithilfe von Ereignissen zu erkennen?

Answer 1

Soweit ich verstehen kann, gibt es kein Textchanged-Ereignis in TextBlock-

(Text-Eigenschaft, deren Änderung in einem Datagrid Ich versuche, für eine Animation zu schaffen, die Textblöcke Hervorhebung). Wenn ich auf Ihre Anforderung eingehe, wäre eine Neugestaltung einer Textbox ebenfalls keine praktikable Lösung. Von meiner vorläufigen Suche, this scheint eine mögliche Lösung zu sein.

Answer 2

Hier ist ein ähnliches Beispiel auf MSDN unter Verwendung von Code-Behind: http://msdn.microsoft.com/en-us/library/system.windows.data.binding.targetupdated.aspx

Answer 3

Dieser aus dem Link in bioskope Antwort, aber Simplied.

<TextBlock Text="{Binding YourTextProperty, NotifyOnTargetUpdated=True}" 
      TargetUpdated="YourTextEventHandler"/> 

Answer 4

Binden Sie die Eigenschaft Text in ein DependencyProperty, die einen Ereignisauslöser hat:

public static string GetTextBoxText(DependencyObject obj) 
{ 
    return (string)obj.GetValue(TextBoxTextProperty); 
} 

public static void SetTextBoxText(DependencyObject obj, string value) 
{ 
    obj.SetValue(TextBoxTextProperty, value); 
} 

public static readonly DependencyProperty TextBoxTextProperty = 
    DependencyProperty.RegisterAttached(
    "TextBoxText", 
    typeof(string), 
    typeof(TextBlockToolTipBehavior), 
    new FrameworkPropertyMetadata(string.Empty, TextBoxTextChangedCallback) 
    ); 

private static void TextBoxTextChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) 
{ 
    TextBlock textBlock = d as TextBlock; 
    HandleTextChange(textBlock); 
} 

Im XAML binden an den Textblock Text Eigentum:

<TextBlock 
Text="{Binding SomeProperty, UpdateSourceTrigger=PropertyChanged}" 
    th:TextBlockBehavior.TextBoxText="{Binding Text, 
    RelativeSource={RelativeSource Self}}" /> 

Answer 5

Hier ist etwas, das Sie verwenden können, Ich habe von Jerry Nixon und Daren May in der Microsoft Virtual Academy "Developing Universal Windows Apps with C# and XAML" abgeholt und der Code, der die DependencyObject-Logik enthält, ist hier "(W8.1-WP8.1) UNIVERSAL APP FOR MVA".

namespace App1.Behaviors 
{ 
// <summary> 
/// Helper class that allows you to monitor a property corresponding to a dependency property 
/// on some object for changes and have an event raised from 
/// the instance of this helper that you can handle. 
/// Usage: Construct an instance, passing in the object and the name of the normal .NET property that 
/// wraps a DependencyProperty, then subscribe to the PropertyChanged event on this helper instance. 
/// Your subscriber will be called whenever the source DependencyProperty changes. 
/// </summary> 
public class DependencyPropertyChangedHelper : DependencyObject 
{ 
    /// <summary> 
    /// Constructor for the helper. 
    /// </summary> 
    /// <param name="source">Source object that exposes the DependencyProperty you wish to monitor.</param> 
    /// <param name="propertyPath">The name of the property on that object that you want to monitor.</param> 
    public DependencyPropertyChangedHelper(DependencyObject source, string propertyPath) 
    { 
     // Set up a binding that flows changes from the source DependencyProperty through to a DP contained by this helper 
     Binding binding = new Binding 
     { 
      Source = source, 
      Path = new PropertyPath(propertyPath) 
     }; 
     BindingOperations.SetBinding(this, HelperProperty, binding); 
    } 

    /// <summary> 
    /// Dependency property that is used to hook property change events when an internal binding causes its value to change. 
    /// This is only public because the DependencyProperty syntax requires it to be, do not use this property directly in your code. 
    /// </summary> 
    public static DependencyProperty HelperProperty = 
     DependencyProperty.Register("Helper", typeof(object), typeof(DependencyPropertyChangedHelper), new PropertyMetadata(null, OnPropertyChanged)); 

    /// <summary> 
    /// Wrapper property for a helper DependencyProperty used by this class. Only public because the DependencyProperty syntax requires it. 
    /// DO NOT use this property directly. 
    /// </summary> 
    public object Helper 
    { 
     get { return (object)GetValue(HelperProperty); } 
     set { SetValue(HelperProperty, value); } 
    } 

    // When our dependency property gets set by the binding, trigger the property changed event that the user of this helper can subscribe to 
    private static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) 
    { 
     var helper = (DependencyPropertyChangedHelper)d; 
     helper.PropertyChanged(d, e); 
    } 

    /// <summary> 
    /// This event will be raised whenever the source object property changes, and carries along the before and after values 
    /// </summary> 
    public event EventHandler<DependencyPropertyChangedEventArgs> PropertyChanged = delegate { }; 
} 
} 

Nutzungs XAML:

<TextBlock Grid.Row="0" 
     x:Name="WritingMenuTitle" 
     HorizontalAlignment="Left" 
     FontSize="32" 
     FontWeight="SemiBold" 
     Text="{Binding WritingMenu.Title}" 
     TextAlignment="Left" 
     TextWrapping="Wrap"/> 

Nutzungs xaml.cs:

Behaviors.DependencyPropertyChangedHelper helper = new Behaviors.DependencyPropertyChangedHelper(this.WritingMenuTitle, Models.CommonNames.TextBlockText); 
helper.PropertyChanged += viewModel.OnSenarioTextBlockTextChangedEvent; 

Nutzungs viewmodel.cs:

public async void OnSenarioTextBlockTextChangedEvent(object sender, DependencyPropertyChangedEventArgs args) 
{ 
StringBuilder sMsg = new StringBuilder(); 

try 
{ 
    Debug.WriteLine(String.Format(".....WritingMenuTitle : New ({0}), Old ({1})", args.NewValue, args.OldValue)); 
} 
catch (Exception msg) 
{ 
    #region Exception 
    ..... 
    #endregion 
} 
} 

Answer 6

Sein leichter als das lol. Späte Antwort, aber viel einfacher.

// assume textBlock is your TextBlock 
DependencyPropertyDescriptor dp = DependencyPropertyDescriptor.FromProperty(TextBlock.TextProperty, typeof(TextBlock)); 

dp.AddValueChanged(textBlock, (object a, EventArgs b) => 
{ 
     MessageBox.Show("text changed"); 
});