.Net6 调用qq邮箱发送邮件

1.appsettings.json 写入需要用到的基本信息

2.发送消息核心方法

public class SendHelperl
    {
        private readonly IConfiguration _configuration;

        public SendHelperl(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        /// <summary>
        /// 发送邮件方法
        /// </summary>
        /// <param name="mailTo">接收人邮件</param>
        /// <param name="mailTitle">发送邮件标题</param>
        /// <param name="mailContent">发送邮件内容</param>
        /// <returns></returns>
        public bool SendEmail(string mailTo, string mailTitle, string mailContent)
        {
            MailSetting mailSetting = new MailSetting();
            _configuration.Bind("MailSetting", mailSetting);

            //设置发送方邮件信息，例如：qq邮箱
            string stmpServer = mailSetting.StmpServer;//smtp服务器地址
            string mailAccount = mailSetting.MailAccount;//邮箱账号
            string pwd = mailSetting.Code;//邮箱密码（qq邮箱此处使用授权码，其他邮箱见邮箱规定使用的是邮箱密码还是授权码）

            //邮件服务设置
            SmtpClient smtpClient = new SmtpClient();
            smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;//指定电子邮件发送方式
            smtpClient.Host = stmpServer;//指定发送方SMTP服务器
            smtpClient.EnableSsl = true;//使用安全加密连接
            smtpClient.UseDefaultCredentials = false;//不和请求一起发送
            smtpClient.Credentials = new NetworkCredential(mailAccount, pwd);//设置发送账号密码

            MailMessage mailMessage = new MailMessage(mailAccount, mailTo);//实例化邮件信息实体并设置发送方和接收方
            mailMessage.Subject = mailTitle;//设置发送邮件得标题
            mailMessage.Body = mailContent;//设置发送邮件内容
            mailMessage.BodyEncoding = Encoding.UTF8;//设置发送邮件得编码
            mailMessage.IsBodyHtml = false;//设置标题是否为HTML格式
            mailMessage.Priority = MailPriority.Normal;//设置邮件发送优先级

            try
            {
                smtpClient.Send(mailMessage);//发送邮件
                return true;
            }
            catch (SmtpException ex)
            {
                throw ex;
            }
        }
    }

    public class MailSetting
    {
        public string Code { get; set; }
        public string? PassWord { get; set; }
        public string MailAccount { get; set; }
        public string StmpServer { get; set; }
    }

3.常见问题

Bad sequence of commands. The server response was: Error: need EHLO and AUTH first !

首先确定你的邮箱是否有授权，appsettings.json里面的授权码就是从这里来的

登录你的QQ邮箱，进入设置里面找到账户，开启红线处的服务，按照操作一步步往下，最后会生成一个授权码，将授权码复制到 appsettings.json的 code中

设置完成之后若还是报一样的错误，查看代码　　 smtpClient.UseDefaultCredentials　　需要设置成false