C# 发送邮件，MimeMessage 配置

 /// <summary>
        /// 同步发送邮件
        /// </summary>
        /// <param name="host">主机--QQ邮箱默认smtp.qq.com</param>
        /// <param name="port">端口--QQ邮箱默认465</param>
        /// <param name="account">账号 --邮箱地址发件人</param>
        /// <param name="password">密码 --第一步获取的授权码</param>
        /// <param name="message">邮件模型</param>
        /// <returns></returns>
        public static Exception Send(string host, int port, string account, string password, MimeMessage message)
        {
            try
            {
                using (var client = new SmtpClient())
                {
                    client.Timeout = 5000;
                    client.Connect(host, port, true);
                    client.Authenticate(account, password);

                    client.Send(message);

                    client.Disconnect(true);
                }

                return null;
            }
            catch (Exception e)
            {
                return e;
            }
        }

        public async Task  Emailadd (Guid? id, ERPMarketingEmail Email, List<ERPMarketingCustomer> customlist, AppSettings appSettingService, Guid UserID)
        {
            using (var scope = _serviceScopeFactory.CreateScope())
            {
                var dbContext = scope.ServiceProvider.GetService<UnitemillManageDbContext>();

                MimeMessage message = new MimeMessage();//实例化对象
                message.From.Add(new MailboxAddress(Encoding.UTF8, appSettingService.DisplayName, appSettingService.From));//配置邮件的显示名称和发送账户
                if (Email != null)
                {

                    message.Subject = Email.Title;//邮件的标题
                    var bodyBuilder = new BodyBuilder();
                    bodyBuilder.HtmlBody = Email.Text;
                    message.Body = bodyBuilder.ToMessageBody();//这是邮件的内容，通过BodyBuilder将text文本转换成HTML的body,并且赋值给body
                }
                if (customlist.Count > 0)
                {
                    foreach (var oneCustom in customlist)
                    {
                        message.Bcc.Clear();
                        message.To.Clear();
                        if (appSettingService.IsBCC)//这个位置是验证接收客户的邮箱是不是隐匿发送（不确定往to里加就行）
                        {
                            message.Bcc.Add(new MailboxAddress(oneCustom.Email));

 }

else { message.To.Add(new MailboxAddress(oneCustom.Email));//message.to 可以继续添加，我这里是考虑到服务器的压力所以一个客户发一次 } int r = new Random().Next(10, 45); System.Threading.Thread.Sleep(r * 1000); Email.CreateDate = DateTime.Now; Email.CreateUserId = UserID; var ex = SMTPHelper.Send(appSettingService.Host, appSettingService.Port, appSettingService.UserName, appSettingService.Password, message);
                        //调用上面的方法执行发送操作，发送完成记得数据库加一行记录啊如下
                        if (ex == null)
                        {
                           成功，添加日志
                        }
                        else
                        {
                           失败，添加日志
                        }

                    }
                }
            }
        }