MailMessage mailMsg = new MailMessage();
mailMsg.From = new MailAddress("发送人邮箱帐号", "发送人昵称");
mailMsg.To.Add(new MailAddress("收件人地址", "收件人昵称"));
mailMsg.Subject = txtTitle.Text;//标题
mailMsg.Body = txtMail.Text;
mailMsg.IsBodyHtml = true;//正文可以为html
mailMsg.BodyEncoding = Encoding.GetEncoding("GB2312");
SmtpClient client = new SmtpClient("smtp.live.com");//发送邮箱服务器
client.EnableSsl = true;//要求安全连接的,hotmail需要,网易,QQ不用
client.Credentials = new NetworkCredential("发送人的账号", "发送人的密码");
client.Send(mailMsg);