Continuous asynchronous Ping using TAP and IProgress in C#5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;


/// From Mark Heath's blog Sound Code:
/// http://mark-dot-net.blogspot.de/2010/11/how-to-invoke-command-on-viewmodel-by.html
/// 
namespace PingWpf.ViewModels
{
    public static class EnterKeyHelpers
    {
        public static ICommand GetEnterKeyCommand(DependencyObject target)
        {
            return (ICommand)target.GetValue(EnterKeyCommandProperty);
        }

        public static void SetEnterKeyCommand(DependencyObject target, ICommand value)
        {
            target.SetValue(EnterKeyCommandProperty, value);
        }

        public static readonly DependencyProperty EnterKeyCommandProperty =
            DependencyProperty.RegisterAttached(
                "EnterKeyCommand",
                typeof(ICommand),
                typeof(EnterKeyHelpers),
                new PropertyMetadata(null, OnEnterKeyCommandChanged));

        static void OnEnterKeyCommandChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
        {
            ICommand command = (ICommand)e.NewValue;
            FrameworkElement fe = (FrameworkElement)target;
            Control control = (Control)target;
            control.KeyDown += (s, args) =>
                {
                    if (args.Key == Key.Enter)
                    {
                        // make sure the textbox binding updates its source first   
                        BindingExpression b = control.GetBindingExpression(TextBox.TextProperty);
                        if (b != null)
                        {
                            b.UpdateSource();
                        }
                        command.Execute(null);
                    }
                };
        }
    }


}