System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient();
        //这里使用QQ的邮箱来发送测试，如果是其它邮箱，请根据其它邮箱POP3/IMAP/SMTP服务来设置

        client.Host = "smtp.qq.com";
        client.UseDefaultCredentials = false;
        client.Credentials = new System.Net.NetworkCredential("6你的邮箱www.jb51.net", "***密码***");
        client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
        System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage("60**你的*www.jb51.net"541**收件人的www.jb51.net");
        message.Subject = "主题";
        message.Body = "内容";
        message.BodyEncoding = System.Text.Encoding.UTF8;
        message.IsBodyHtml = true;

        try
        {
            client.Send(message);

        }
        catch
        {

        }

    }