Receive Whatsapp Message using WhastApp API 1.2.2 (Nuget) in C#

Question

I use visual studio 2012 and I use whatsap api in my project (downloaded from Nuget), I already develop some code to send whatsapp message to another number, but I want to know how can i receive message from other numbers? which event should i use? and how to keep my application always listen to incoming messages.

my code to send is:

 static string from = "9********";
 static WhatsApp wa = new WhatsApp(from, "*******w=", "Az", false, true);

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            string to = txt_To.Text.Trim();
            string msg = txt_Message.Text.Trim();

            wa.OnConnectSuccess += () =>
            {
                MessageBox.Show("Connected Successfully");

                wa.OnLoginSuccess += (phoneNumber, data) =>
                    {
                        wa.SendMessage(to, msg);
                        MessageBox.Show("Message Sent ...");

                    };

                wa.OnLoginFailed += (data) =>
                    {
                        MessageBox.Show("Login Faild ...");

                    };
                wa.Login();

            };

            wa.OnConnectFailed += (ex) =>
                {
                    MessageBox.Show("Connected Faild ...");

                };

            wa.Connect();
            wa.Login();
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

    }

My application is wondows application

any one can help me?