Question

Is there any way, how to force ObservableCollection to fire CollectionChanged?

I have a ObservableCollection of objects ListBox item source, so every time I add/remove item to collection, ListBox changes accordingly, but when I change properties of some objects in collection, ListBox still renders the old values.

Even if I do modify some properties and then add/remove object to the collection, nothing happens, I still see old values.

Is there any other way around to do this? I found interface INotifyPropertyChanged, but I don’t know how to use it.

Answer 1

I agree with Matt’s comments above. Here’s a small piece of code to show how to implement the INotifyPropertyChanged.

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Code-behind
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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Data; using System.Windows.Documents;  namespace WpfApplication1 {        /// <summary>     /// Interaction logic for Window1.xaml     /// </summary>     public partial class Window1 : Window     {         Nicknames names;          public Window1()         {             InitializeComponent();             this.addButton.Click += addButton_Click;             this.names = new Nicknames();             dockPanel.DataContext = this.names;         }          void addButton_Click(object sender, RoutedEventArgs e)         {             this.names.Add(new Nickname(myName.Text, myNick.Text));         } } public class Nicknames : System.Collections.ObjectModel.ObservableCollection<Nickname> { }  public class Nickname : System.ComponentModel.INotifyPropertyChanged {     public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;     void Notify(string propName)     {         if (PropertyChanged != null)         {             PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propName));         }     }      string name;     public string Name     {         get { return name; }         set         {             name = value;             Notify('Name');         }     }     string nick;     public string Nick     {         get { return nick; }         set         {             nick = value;             Notify('Nick');         }     }     public Nickname() : this('name', 'nick') { }     public Nickname(string name, string nick)     {         this.name = name;         this.nick = nick;     }      public override string ToString()     {         return Name.ToString() + ' ' + Nick.ToString();     }   } } 

XAML

<Window x:Class='WpfApplication1.Window1' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' Title='Window1' Height='300' Width='300'> <Grid>     <DockPanel x:Name='dockPanel'>         <TextBlock DockPanel.Dock='Top'>         <TextBlock VerticalAlignment='Center'>Name: </TextBlock>         <TextBox Text='{Binding Path=Name}' Name='myName' />         <TextBlock VerticalAlignment='Center'>Nick: </TextBlock>         <TextBox Text='{Binding Path=Nick}' Name='myNick' />         </TextBlock>         <Button DockPanel.Dock='Bottom' x:Name='addButton'>Add</Button>         <ListBox ItemsSource='{Binding}' IsSynchronizedWithCurrentItem='True' />     </DockPanel> </Grid>