using System.Net.Mail;
 

　　　MailMessage m = new MailMessage();
        string FromEmail = "";
        string FromEmailPass = "";
        m.Body = "内容";
        m.Subject = "邮件标题";
        m.From = new MailAddress(FromEmail,"自定义显示");
        m.To.Add("to1@qq.com");
        m.To.Add("to2@qq.com");
        #region  不需要改动
        m.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;
        m.IsBodyHtml = true; //是否为html格式
        m.Priority = MailPriority.High; //发送邮件的优先等级
        m.IsBodyHtml = true;
        m.Priority = MailPriority.Normal;
        m.SubjectEncoding = System.Text.Encoding.UTF8;
        m.BodyEncoding = System.Text.Encoding.UTF8;
        #endregion
        SmtpClient sc = new SmtpClient();
        sc.Host = "smtp.qq.com"; //不同的邮箱对应的值不同
        sc.EnableSsl = false;//**
        sc.UseDefaultCredentials = false;//**
        sc.DeliveryMethod = SmtpDeliveryMethod.Network;
        sc.Credentials = new System.Net.NetworkCredential(FromEmail, FromEmailPass); //指定登录服务器的用户名和密码
        try
        {
            sc.Send(m);
        }
        catch (Exception ex)
        {
            string a = ex.ToString();

        }