Why are you doing it that way. The accepted way would be like this:
System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage();
message.To.Add("emailAddress@yourPlace.com");
message.Subject = "Put a subject here";
message.From = new System.Net.Mail.MailAddress("emailFromAddress@someplace.com");
message.Body = "Put your message here";
System.Net.Mail.SmtpClient smtp = new System.Net.Mail.SmtpClient("yoursmtphost");
smtp.Send(message);