Quick Workaround To GUI Update In Property Change Of Observable Collection

It seems that when adding or removing elements from an observable collection, data binding works (assuming items do not implement INotifyPropertyChanged). However, when an element within the collection changes value, the GUI element is not updated.

My XAML Code

<Button Content="Add" HorizontalAlignment="Left" Margin="366,69,0,0" VerticalAlignment="Top" Width="75" Click="AddDate" />  
<ListBox Name="MyListBox" HorizontalAlignment="Left" Height="95" Margin="131,84,0,0" VerticalAlignment="Top" Width="197">  
    <ListBox.ItemTemplate>  
        <DataTemplate>  
            <StackPanel Orientation="Horizontal">  
                <TextBlock Text="{Binding Now}"></TextBlock>  
                <CheckBox IsChecked="{Binding IsChecked}"></CheckBox>  
            </StackPanel>  
        </DataTemplate>  
    </ListBox.ItemTemplate>  
</ListBox>  
<Button Content="Mark All" HorizontalAlignment="Left" Margin="366,94,0,0" VerticalAlignment="Top" Width="75" Click="MarkAll" />  
<Button Content="Unmark All" HorizontalAlignment="Left" Margin="366,119,0,0" VerticalAlignment="Top" Width="75" Click="UnMarkAll" />

Class file

namespace WpfApp1 {  
    //create our test class  
    public class NowDate {  
        public string Now {  
            get;  
            set;  
        }  
        public bool IsChecked {  
            get;  
            set;  
        }  
    }  
    //create a new collection class with a refresh method  
    public class ObservableCollectionPropertyNotify < T > : ObservableCollection < T > {  
        //OnCollectionChange method is protected, accesible only within a child class in this case. This is why  
        //I made a new Collection class with a public method Refresh.  
        public void Refresh() {  
            for (var i = 0; i < this.Count(); i++) {  
                this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));  
            }  
        }  
    }  
    public partial class MainWindow: Window {  
        public ObservableCollectionPropertyNotify < NowDate > Dates {  
            get;  
            set;  
        }  
        public MainWindow() {  
            InitializeComponent();  
            //Set up a simple collection with some items.  
            Dates = new ObservableCollectionPropertyNotify < NowDate > {  
                new NowDate {  
                    Now = "1", IsChecked = false  
                },  
                new NowDate {  
                    Now = DateTime.Now.ToString(), IsChecked = false  
                }  
            };  
            MyListBox.DataContext = this;  
            MyListBox.ItemsSource = Dates;  
        }  
        private void AddDate(object sender, RoutedEventArgs e) {  
            //in this case GUI updates implicitly. No need to call Refres()  
            Dates.Add(new NowDate {  
                Now = DateTime.Now.ToString(), IsChecked = true  
            });  
        }  
        private void MarkAll(object sender, RoutedEventArgs e) {  
            foreach(var item in Dates)  
            item.IsChecked = true;  
            //calling refresh after item has changed  
            Dates.Refresh();  
        }  
        private void UnMarkAll(object sender, RoutedEventArgs e) {  
            //calling refresh after item has changed  
            foreach(var item in Dates)  
            item.IsChecked = false;  
            Dates.Refresh();  
        }  
    }  
}

• When adding a new item – GUI updates.
• When clicking mark all – GUI updates instantly.
• When clicking unmark all – GUI updates instantly.