C#

private void barButtonItemStartRec_ItemClick(object sender, ItemClickEventArgs e)
        {
            barButtonItemStartRec.Enabled = !(barButtonItemStopRec.Enabled = true);            

            var dlg = new MainForm();
            BackgroundWorker recWorker = new BackgroundWorker();
            recWorker.DoWork += dlg.StartRec;
            recWorker.RunWorkerAsync();          
        }
        
private void barButtonItemStopRec_ItemClick(object sender, ItemClickEventArgs e)
        {            
            barButtonItemStartRec.Enabled = !(barButtonItemStopRec.Enabled = false);
            var dlg = new MainForm();
            dlg.StopRec();            
        }

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Mail;

namespace emailC
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                using (MailMessage mail = new MailMessage())
                {
                    using (SmtpClient smtp = new SmtpClient("smtp.mail.yahoo.com", 587))
                    {
                        mail.From = new MailAddress("fgelana@yahoo.com");
                        mail.To.Add("fraolgela@gmail.com");
                        mail.Subject = "C# Email";
                        mail.Body = "This is for testing SMTP mail for yahoo using C#";
                        smtp.Credentials = new System.Net.NetworkCredential("name@yahoo.com", "password");
                        smtp.EnableSsl = false;
                        smtp.Send(mail);
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }
    }
}