Send Mail: from Contact for feed back

 protected void SendMail()
    {
        // Gmail Address from where you send the mail
        var fromAddress = "gmail@gmail.com";
        // any address where the email will be sending
        var toAddress = YourEmail.Text.ToString();
        //Password of your gmail address
        const string fromPassword = "*******";
        // Passing the values and make a email formate to display
        string subject = YourSubject.Text.ToString();
        string body = "From: " + YourName.Text + "\n";
        body += "Email: " + YourEmail.Text + "\n";
        body += "Subject: " + YourSubject.Text + "\n";
        body += "Question: \n" + Comments.Text + "\n";
        // smtp settings
        var smtp = new System.Net.Mail.SmtpClient();
        {
            smtp.Host = "smtp.gmail.com";
            smtp.Port = 587;
            smtp.EnableSsl = true;
            smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
            smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);

            smtp.Timeout = 20000;
        }
        // Passing values to smtp object
        smtp.Send(fromAddress, toAddress, subject, body);
    }
    protected void BtnSend_Click(object sender, EventArgs e)
    {
        try
        {
            //here on button click what will done
            SendMail();
            DisplayMessage.Text = "Your Comments after sending the mail";
            DisplayMessage.Visible = true;
            YourSubject.Text = "";
            YourEmail.Text = "";
            YourName.Text = "";
            Comments.Text = "";
        }
        catch (Exception ex) { throw ex; }
    }



Design: