Send Email From Contact Us Form

I am using surface controller to send the email.I define the “From Email” ([email protected]) hard coded. But now I want that the admin update the “From Email” field whenever they want.so How can I get the value of email field from admin panel using Datatype. /umbraco.

MailAddress from = new MailAddress(“[email protected]”,
“testproject”);

 [HttpPost]
        public int SendMail(MessageModel model)
        {
            if (ModelState.IsValid)
            {
                try
                {
                    string subject = "From: " + model.Email;
                    string body = model.Message;

                    var smtp = new SmtpClient
                    {
                        Host = "smtp.gmail.com",
                        Port = 587,
                        EnableSsl = true,
                        DeliveryMethod = SmtpDeliveryMethod.Network,
                        UseDefaultCredentials = false,
                        Credentials = new NetworkCredential("[email protected]", "abc123#!")
                    };
                    body = PopulateEmailBody(model.Name, model.Email, model.Mobile, model.Message);

                    MailAddress from = new MailAddress("[email protected]", "testproject");
                    MailAddress to = new MailAddress(model.Email,model.Name);
                    MailMessage message = new MailMessage(from, to);
                    message.Subject = subject;
                    message.IsBodyHtml = true;
                    message.Body = body;
                    SmtpClient client = smtp;
                    client.Send(message);
                    //TempData.Add("Success", true);
                    return 1;
                }
                catch (Exception ex)
                {
                    return -1;
                }
            }
            else
                return -1;

        }

This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/85528-send-email-from-contact-us-form