Sending Mail (C#)

Take a windows form. Take a textbox from toolbox and change the name of the textbox. i change it to emailToTextBox. Another textbox for subject and chance to subjectFromTextBox.Another RichTextBox for body of the mail. bodyRichTextBox.Now take a button and write the code behind the button

[ smtp.Host = ""; //Like "smtp.gmail.com" ]

        private void sendMessageButton_Click(object sender, EventArgs e)

        {

            string to = emailToTextBox.Text;

            string subject = subjectFromTextBox.Text;

            string mailBody = bodyrRichTextBox.Text;

            if (to == "" && subject == "" && mailBody == "")

            {

            }

            else

            {

                MailMessage msg = new MailMessage();

                msg.To.Add(to);

                msg.From = new MailAddress(to);

                msg.Subject = subject;

                msg.Body = mailBody;

                msg.IsBodyHtml = true;

                SmtpClient smtp = new SmtpClient();

                smtp.Host = "";  

                smtp.Credentials = new System.Net.NetworkCredential("x@y.com", "passxyz");

                smtp.EnableSsl = true;

                try

                {

                    smtp.Send(msg);

                    MessageBox.Show("Message Has Been Sent.");

                }

                catch

                {

                    MessageBox.Show("Message can't send...");

                }

            }