c# email send

MailAddress from = new MailAddress("swshq781@163.com");
        MailAddress to = new MailAddress(txtTo.Text.ToString().Trim());
        MailMessage message = new MailMessage(from, to);
        //message.Subject = "ShoppingCity取回密码";
        message.Subject = txtSubject.Text.ToString().Trim();
        message.IsBodyHtml = true;
        //message.Body = name + ",您的密码是:" + pwd;
        message.Body = txtBody.Text.ToString().Trim();
        message.BodyEncoding = Encoding.GetEncoding("GB2312");
        SmtpClient client = new SmtpClient();
        client.Host = "smtp.163.com";

        client.UseDefaultCredentials = true;
        client.Credentials = new NetworkCredential("swshq781@163.com", "111111");
        client.DeliveryMethod = SmtpDeliveryMethod.Network;
        client.Send(message);