Event traffic calming

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;

using SampleDomain;
using TrafficCalming;

namespace CalmedClient
{
    public partial class MainForm : Form
    {
        private readonly OrderRepository _ordersRepository = new OrderRepository();
        private readonly EventCalmer _calmer = new EventCalmer(TimeSpan.FromSeconds(5));
        
        private DateTime _lastTimeUpdatedAt = DateTime.MinValue;
        
        public MainForm()
        {       
            InitializeComponent();
            
            _ordersRepository.OrderArrived += _calmer.HandleEvent;
            _calmer.EventOccurred += HandleOrderArrived;
        }
        
        private void HandleOrderArrived(object sender, EventArgs e)
        {
            if (Handle == IntPtr.Zero)
                return;
                
            this.Invoke(new Action(UpdateOrdersGrid));
        }
        
        private void UpdateOrdersGrid()
        {
            var orders = _ordersRepository.ListFrom(_lastTimeUpdatedAt).ToList();
            
            _ordersGrid.DataSource = orders ;
            
            _lastTimeUpdatedAt = DateTime.Now;
        }
        
        private void MainFormLoad(object sender, System.EventArgs e)
        {
            _ordersRepository.StartGenerating();
        }
        
        private void Button1Click(object sender, System.EventArgs e)
        {
            MessageBox.Show(this, "Button clicked", "Info", 
                            MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
    }
}