发邮件方法

 public static bool mailyanzhen(string receivemail, string code, string smtpname, string sendnumber, string sendpassword, string emailtitle)
    {
        bool bl = false;

        ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
        System.Net.Mail.SmtpClient client = new SmtpClient();
        client.Host = smtpname;
        client.Port = 587; //默认的25端口现在不能用了//qq邮箱端口587//阿里企业邮箱25（SSL加密端口为465）
        client.EnableSsl = true;
        client.UseDefaultCredentials = true;
        client.Credentials = new System.Net.NetworkCredential(sendnumber, sendpassword);
        client.DeliveryMethod = SmtpDeliveryMethod.Network;
        MailMessage message = new MailMessage(sendnumber, receivemail);
        message.Subject = emailtitle;//邮件主题


        message.Body = code;//邮件内容
        message.BodyEncoding = System.Text.Encoding.UTF8;//邮件正文的编码方式
        message.SubjectEncoding = Encoding.GetEncoding(936);
        message.Priority = System.Net.Mail.MailPriority.High;
        message.IsBodyHtml = true;  //邮件内容是否为html格式
        //发送邮件
        try
        {
            client.Send(message);
            bl = true;
        }
        catch (Exception e)
        {
            HttpContext.Current.Response.Write(e.ToString());
            HttpContext.Current.Response.End();

            bl = false;
        }
        return bl;
    }