fullcode.cs

public partial class Form1 : Form
    {
        private HubConnection connection;

        public Form1()
        {
            InitializeComponent();
        }

        private void button_start_Click(object sender, EventArgs e)
        {
            var login = "admin";
            var tenant = "Cmp1";
            var password = "123";

            // Set up a Basic authentication token 
            var basicAuthToken = Convert.ToBase64String(Encoding.UTF8.GetBytes(login + "@" + tenant + ":" + password));
            
            //Connect to an Acumatica ERP instance
            connection = new HubConnection("https://localhost/PushNotifications");
            connection.Headers.Add("Authorization", "Basic " + basicAuthToken);

            //Create a proxy to hub
            //Use "PushNotificationsHub" as the address of the hub
            var myHub = connection.CreateHubProxy("PushNotificationsHub");
            connection.Start().ContinueWith(task =>
            {
                try
                {
                    if (task.IsFaulted)
                    {
                        MessageBox.Show("There was an error during open of the connection: " +
                                        task.Exception.GetBaseException());
                    }
                    else
                    {
                        //Instead of "TestNotification", specify the name 
                        //that you specified on the Push Notifications form
                        myHub.Invoke<string>("Subscribe", "TestNotification").Wait();
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error: " + ex.Message.ToString());
                }
            }).Wait();

            myHub.On<NotificationResult>("ReceiveNotification", nr =>
            {
                // updated data
                if (nr.Inserted.Length > 0 && nr.Deleted.Length > 0)
                {
                    MessageBox.Show("Before update " + JsonConvert.DeserializeObject(nr.Deleted[0].ToString()));
                    MessageBox.Show("After update " + JsonConvert.DeserializeObject(nr.Inserted[0].ToString()));
                }
                else
                {
                    // inserted data
                    if (nr.Inserted.Length > 0)
                        MessageBox.Show("Inserted " + JsonConvert.DeserializeObject(nr.Inserted[0].ToString()));

                    // deleted data
                    if (nr.Deleted.Length > 0)
                        MessageBox.Show("Deleted " + JsonConvert.DeserializeObject(nr.Deleted[0].ToString()));
                }
            });

            button_start.Enabled = false;
            button_stop.Enabled = true;
        }

        private void button_stop_Click(object sender, EventArgs e)
        {
            connection.Stop();

            button_start.Enabled = true;
            button_stop.Enabled = false;
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            connection.Stop();
        }
    }