c# - Asp.net:如何修复向多个收件人发送邮件时引发的异常？erroline:在邮件 header 中发现无效字符: ','

Question

当我尝试从数据库中获取电子邮件数据来发送电子邮件时，此行 message.To.Add(mailTo); 出现错误。

 void Sendmail_Click(object sender, EventArgs e)
        {

            List<DAL.Customer> mailId = (from rs in General.db.Customers
                                         where rs.IsActive == true
                                         select rs).ToList();

            StringBuilder mailstring = new StringBuilder();

                foreach (var item in mailId)
                {

                        mailstring.Append(item.Email).Append(",");

                }

            string mailTo = mailstring.ToString();

            if (mailTo.EndsWith(","))
            {

                mailTo = mailTo.Remove(mailTo.LastIndexOf(","));
            }


            SmtpClient smtp = new SmtpClient();
            mailMessage.From = fromMail;
            mailMessage.To.Add(new MailAddress(mailTo));

            mailMessage.IsBodyHtml = true;



            lblStatus.Text = "Email sent successfully";



    }

Answer 1

请看一下这个。我不知道凭据，因此我假设您可以将它们添加起来。

void Sendmail_Click(object sender, EventArgs e)
        {

            List<DAL.Customer> mailId = (from rs in General.db.Customers
                                         where rs.IsActive == true
                                         select rs).ToList();

            SmtpClient smtp = new SmtpClient();
            mailMessage.From = fromMail;
            mailMessage.IsBodyHtml = true;

            foreach (var item in mailId)
            {
               mailMessage.To.Add(new MailAddress(item.Email));
            }
            lblStatus.Text = "Email sent successfully";

    }