Send mail using gmail account from C#

            try
            {
                //Creating the object of MailMessage
                MailMessage message = new MailMessage();

                //Creating the object of SmtpClient
                SmtpClient smtp = new SmtpClient();

                //To Emial Address
                message.To.Add(new MailAddress("To Email Address"));

                //From Email Address
                message.From = new MailAddress("From Email Address");

                //It is a subject of your email
                message.Subject = "Test";

                //Body of the mail
                message.Body = "Content";

                //Set the true if Html Body , otherwise false
                message.IsBodyHtml = true;

                //set the priority of email
                message.Priority = MailPriority.High;

                smtp.Port = 587;

                smtp.Host = "smtp.gmail.com";

                smtp.EnableSsl = true;

                smtp.UseDefaultCredentials = false;

                //Set credentials of your email from email will be send
                smtp.Credentials = new NetworkCredential("Gmail UserName", "Gmail Pwd");

                smtp.DeliveryMethod = SmtpDeliveryMethod.Network;

                smtp.Send(message);
            }
            catch (Exception ex)
            {
                //Handle the exception here
            }

            You must need to turn on less security for your account using below link

            https://www.google.com/settings/security/lesssecureapps