WPF C#

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="200" Width="300"
    Loaded="Window_Loaded">
    
        
            
                
            
        
    

    
        
    


//File:Window.xaml.cs
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Threading;
namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        private ObservableCollection numberDescriptions;
        public Window1()
        {
            InitializeComponent();
        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            numberDescriptions = new ObservableCollection();
            listBox.ItemsSource = numberDescriptions;
            this.Dispatcher.BeginInvoke(DispatcherPriority.Background,new LoadNumberDelegate(LoadNumber), 1);
        }
        private delegate void LoadNumberDelegate(int number);
        private void LoadNumber(int number)
        {
            numberDescriptions.Add("Number " + number.ToString());
            this.Dispatcher.BeginInvoke(DispatcherPriority.Background,new LoadNumberDelegate(LoadNumber), ++number);
        }
    }
}