SmtpClient client = new SmtpClient("smtp.gmail.com");
                client.Port = 587;
                client.EnableSsl = true;
                client.Timeout = 100000;
                client.DeliveryMethod = SmtpDeliveryMethod.Network;
                client.UseDefaultCredentials = false;
                client.Credentials = new NetworkCredential(
                  "r.pradeep1007@gmail.com", "9943696959");
                MailMessage msg = new MailMessage();
                msg.To.Add(textBox1.Text);
                msg.From = new MailAddress("yourid@gmail.com");
                msg.Subject = textBox3.Text;
                msg.Body = richTextBox1.Text;
                Attachment data = new Attachment(textBox2.Text);
                msg.Attachments.Add(data);
                client.Send(msg);
                MessageBox.Show("Successfully Sent Message.");