/// <summary>
    /// Email助手
    /// </summary>
    public class EmailHelper
    {
        #region 发送邮件

        /// <summary>
        /// 发送邮件,无符件,使用HTML编码
        /// </summary>
        /// <param name="to">接收邮件用户列表,以分号连接</param>
        /// <param name="subject">标题</param>
        /// <param name="body">内容</param>
        /// <returns>是否发送成功</returns>
        public static bool SendMail(string to, string subject, string body)
        {
            return SendMail(to, subject, body, string.Empty, true);
        }

        /// <summary>
        /// 发送邮件,有符件,使用HTML编码
        /// </summary>
        /// <param name="to">接收邮件用户列表,以分号连接</param>
        /// <param name="subject">标题</param>
        /// <param name="body">内容</param>
        /// <param name="attach">符件路径 如:C:\\附件.rar</param>
        /// <returns>是否发送成功</returns>
        public static bool SendMail(string to, string subject, string body, string attach)
        {
            return SendMail(to, subject, body, attach, true);
        }

        /// <summary>
        /// 使用System.Net.Mail的发送邮件.
        /// </summary>
        /// <param name="to">接收邮件用户列表,以分号连接</param>
        /// <param name="subject">标题</param>
        /// <param name="body">内容</param>
        /// <param name="attach">符件</param>
        /// <param name="useHtmlFormat">是否为HTML编码发送</param>
        /// <returns>是否发送成功</returns>
        private static bool SendMail(string to, string subject, string body, string attach, bool useHtmlFormat)
        {
            string from = ConfigHelper.GetAppSettings("FromAddress");
            //邮件发送者的名称
            string FromName = ConfigHelper.GetAppSettings("FromName");
            string sendEmailPassword = ConfigHelper.GetAppSettings("FromPwd").Decrypt();

            MailMessage mailMsg = new MailMessage();
            string[] mails = to.Split(';');
            foreach (string mail in mails)
            {
                if (!String.IsNullOrEmpty(mail))
                {
                    mailMsg.To.Add(mail);
                }
            }
            mailMsg.SubjectEncoding = Encoding.Default;
            mailMsg.BodyEncoding = Encoding.Default;
            mailMsg.From = new MailAddress(from, FromName);
            mailMsg.Subject = subject;
            mailMsg.Body = body;
            if (attach != null && attach != "")
            {
                char[] delim = new char[] { ',' };
                foreach (string sSubstr in attach.Split(delim))
                {
                    //Attachment("C:\\附件.rar");
                    //System.Net.Mail.Attachment MyAttachment = new System.Net.Mail.Attachment(sSubstr);
                    //mailMsg.Attachments.Add(MyAttachment);
                    Attachment attachment = new Attachment(sSubstr, "text/plain");
                    mailMsg.Attachments.Add(attachment);

                }
            }
            if (useHtmlFormat)
                mailMsg.IsBodyHtml = true;
            else
                mailMsg.IsBodyHtml = false;
            SmtpClient client = new SmtpClient();
            //mail.163.com
            client.Host = ConfigHelper.GetAppSettings("FromSmtp");
            //端口通常是25
            client.Port = Convert.ToInt32(ConfigHelper.GetAppSettings("FromSmtpProt"));
            client.UseDefaultCredentials = false;
            //不需要做超时设置,否则经常发不了邮件,net有自已的超时机制.不设只随时都能发送成功的
            //client.Timeout = 60;
            #region Email
            client.Credentials = new System.Net.NetworkCredential(from, sendEmailPassword);
            #endregion
            client.DeliveryMethod = SmtpDeliveryMethod.Network;
            try
            {
                client.Send(mailMsg);
                return true;
            }
            catch (Exception ex)
            {
                Exception source = ex;
                while (source.InnerException != null)
                    source = source.InnerException;
                //XTrace.WriteLog("邮件发送失败！邮件标题：" + subject + "。错误消息：" + source.Message);
                return false;
            }
        }

        /// <summary>
        /// 使用System.Net.Mail的发送邮件.
        /// </summary>
        /// <param name="to">接收邮件用户列表,以分号连接</param>
        /// <param name="subject">标题</param>
        /// <param name="body">内容</param>
        /// <param name="attach">符件</param>
        /// <param name="useHtmlFormat">是否为HTML编码发送</param>
        /// <param name="from">发送者邮件地址</param>
        /// <param name="fromName">发送者称谓</param>
        /// <param name="sendEmailPassword">发送者邮件密码</param>
        /// <param name="fromSmtp">邮件服务器Smtp地址，不加http://</param>
        /// <param name="fromSmtpProt">邮件服务器Smtp端口</param>
        /// <param name="timeOut">超时时间 单位 称</param>
        /// <returns></returns>
        public static bool SendMail(string to, string subject, string body, string attach, bool useHtmlFormat, string from, string fromName, string sendEmailPassword, string fromSmtp, int fromSmtpProt)
        {
            MailMessage mailMsg = new MailMessage();
            string[] mails = to.Split(';');
            foreach (string mail in mails)
            {
                if (!String.IsNullOrEmpty(mail))
                {
                    mailMsg.To.Add(mail);
                }
            }
            mailMsg.SubjectEncoding = Encoding.Default;
            mailMsg.BodyEncoding = Encoding.Default;
            mailMsg.From = new MailAddress(from, fromName);
            mailMsg.Subject = subject;
            mailMsg.Body = body;
            if (attach != null && attach != "")
            {
                char[] delim = new char[] { ',' };
                foreach (string sSubstr in attach.Split(delim))
                {
                    //Attachment("C:\\附件.rar");
                    System.Net.Mail.Attachment MyAttachment = new System.Net.Mail.Attachment(sSubstr);
                    mailMsg.Attachments.Add(MyAttachment);
                }
            }
            if (useHtmlFormat)
                mailMsg.IsBodyHtml = true;
            else
                mailMsg.IsBodyHtml = false;
            SmtpClient client = new SmtpClient();
            //mail.163.com
            client.Host = fromSmtp;
            //端口通常是25
            client.Port = fromSmtpProt;
            client.UseDefaultCredentials = false;
            //client.Timeout = timeOut;
            #region Email
            client.Credentials = new System.Net.NetworkCredential(from, sendEmailPassword);
            #endregion
            client.DeliveryMethod = SmtpDeliveryMethod.Network;
            try
            {
                client.Send(mailMsg);
                return true;
            }
            catch (Exception ex)
            {
                Exception source = ex;
                while (source.InnerException != null)
                    source = source.InnerException;
                //XTrace.WriteLog("邮件发送失败！邮件标题：" + subject + "。错误消息：" + source.Message);
                return false;
            }
        }
        #endregion

    }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Mail;

namespace WebPrint.Framework
{
    public static class SmtpHelper
    {
        /// <summary>
        /// 同步发送
        /// </summary>
        /// <param name="info"></param>
        public static void SendMail(SmtpInformation info)
        {
            var msg = GetMailMessage(info);

            var client = new SmtpClient();
            client.Host = info.Server;
            if (!string.IsNullOrEmpty(info.Username)) client.Credentials = new NetworkCredential(info.Username, info.Password);
            client.Send(msg);

            msg.Dispose();
        }

        /// <summary>
        /// 异步发送
        /// </summary>
        /// <param name="info"></param>
        public static void SendMailAsync(SmtpInformation info)
        {
            var msg = GetMailMessage(info);

            var client = new SmtpClient();
            client.Host = info.Server;
            if (!string.IsNullOrEmpty(info.Username)) client.Credentials = new NetworkCredential(info.Username, info.Password);
            client.SendAsync(msg, msg);
        }

        /// <summary>
        /// 获得 MailMessage 对象
        /// </summary>
        private static MailMessage GetMailMessage(SmtpInformation info)
        {
            var msg = new MailMessage();

            info.ToAddresses
                .Where(addr => !addr.IsNullOrEmpty())
                .Select(addr => addr.ToLower())
                .Distinct()
                .ForEach(addr => msg.To.Add(addr));

            info.CcAddresses
                .Where(addr => !addr.IsNullOrEmpty())
                .Select(addr => addr.ToLower())
                .Distinct()
                .ForEach(addr => msg.CC.Add(addr));

            msg.From = new MailAddress(info.FromAddress, info.FromDisplayName, Encoding.UTF8);//发件人地址（可以随便写），发件人姓名，编码
            msg.Subject = info.Subject;
            msg.SubjectEncoding = Encoding.UTF8;
            msg.Body = info.Body;
            msg.BodyEncoding = Encoding.UTF8;
            msg.IsBodyHtml = true;
            msg.Priority = MailPriority.Normal;

            info.Attachments.ForEach(item => msg.Attachments.Add(item));

            return msg;
        }

        //可以用NVelocity模板引擎
        public static string EmailTemplate(string content, string orderSystemName)
        {
            const string template = "<html><body>"
                             + "Thank you for your confirmation!<br/>"
                             + "You could view the order's detail information via the link below:<br/>"
                             + "{0}<br/><br/>"
                             + "************************************************************************************<br/>"
                             + "This e-mail is sent by the r-pac {1} ordering system automatically.<br/>"
                             + "Please don't reply this e-mail directly!<br/>"
                             + "************************************************************************************<br/>"
                             + "</body></html>";

            return string.Format(template, content, orderSystemName);
        }

        public static string EmailCancelledTemplete(string content, string orderSystemName)
        {
            const string template = "<html><body>"
                                    + "Below order is cancelled:<br/>"
                                    + "{0}<br/><br/>"
                                    + "************************************************************************************<br/>"
                                    + "This e-mail is sent by the r-pac {1} ordering system automatically.<br/>"
                                    + "Please don't reply this e-mail directly!<br/>"
                                    + "************************************************************************************<br/>"
                                    + "</body></html>";

            return string.Format(template, content, orderSystemName);
        }

        public static string EmailReOrderTemplete(string content, string orderSystemName)
        {
            const string template = "<html><body>"
                                    + "Below order is re_order:<br/>"
                                    + "{0}<br/><br/>"
                                    + "************************************************************************************<br/>"
                                    + "This e-mail is sent by the r-pac {1} ordering system automatically.<br/>"
                                    + "Please don't reply this e-mail directly!<br/>"
                                    + "************************************************************************************<br/>"
                                    + "</body></html>";

            return string.Format(template, content, orderSystemName);
        }
    }

    public class SmtpInformation
    {
        public SmtpInformation()
        {
            ToAddresses = new List<string>();
            CcAddresses = new List<string>();
            Attachments = new Attachments();
        }
       
        /// <summary>
        /// 发送邮件服务器地址
        /// </summary>
        public string Server { get; set; }
        /// <summary>
        /// 登陆用户名
        /// </summary>
        public string Username { get; set; }
        /// <summary>
        /// 登陆密码
        /// </summary>
        public string Password { get; set; }
        /// <summary>
        /// 显示发件人email
        /// </summary>
        public string FromAddress { get; set; }
        /// <summary>
        /// 用于显示的发件人名
        /// </summary>
        public string FromDisplayName { get; set; }
        /// <summary>
        /// 收件人列表
        /// </summary>
        public List<string> ToAddresses { get; private set; }
        //抄送人列表
        public List<string> CcAddresses { get; private set; }
        /// <summary>
        /// 主题
        /// </summary>
        public string Subject { get; set; }
        /// <summary>
        /// 邮件内容 HTML格式
        /// </summary>
        public string Body { get; set; }
        /// <summary>
        /// 附件
        /// </summary>
        public Attachments Attachments { get; private set; }
    }

    public class Attachments : IEnumerable<Attachment>
    {
        private readonly List<Attachment> attachments;

        internal Attachments()
        {
            attachments = new List<Attachment>();
        }

        public void Add(string fileName)
        {
            attachments.Add(new Attachment(fileName));
        }

        public void Add(System.IO.Stream contentStream, string name)
        {
            attachments.Add(new Attachment(contentStream, name));
        }

        public void ForEach(Action<Attachment> action)
        {
            attachments.ForEach(action);
        }

        public void Clear()
        {
            attachments.Clear();
        }

        #region IEnumerable<Attachment> 成员

        public IEnumerator<Attachment> GetEnumerator()
        {
            return attachments.GetEnumerator();
        }

        #endregion

        #region IEnumerable 成员

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return this.GetEnumerator();
        }

        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Net.Mime;
using System.Text;

namespace SendMail
{
    public class SendMail
    {
        private MailMessage mailMessage;
        private SmtpClient smtpClient;
        private string password;//发件人密码  
        /// <summary>  
        /// 处审核后类的实例  
        /// </summary>  
        /// <param name="To">收件人地址</param>  
        /// <param name="From">发件人地址</param>  
        /// <param name="Body">邮件正文</param>  
        /// <param name="Title">邮件的主题</param>  
        /// <param name="Password">发件人密码</param>  
        public SendMail(string[] To, string From, string Body, string Title, string Password)
        {
            mailMessage = new MailMessage();
            foreach (var item in To)
            {
                mailMessage.To.Add(item);
            }
            mailMessage.From = new System.Net.Mail.MailAddress(From);
            mailMessage.Subject = Title;
            mailMessage.Body = Body;
            mailMessage.IsBodyHtml = true;
            mailMessage.BodyEncoding = System.Text.Encoding.UTF8;
            mailMessage.Priority = System.Net.Mail.MailPriority.Normal;
            this.password = Password;
        }
        /// <summary>  
        /// 添加附件  
        /// </summary>  
        public void Attachments(string Path)
        {
            string[] path = Path.Split(',');
            Attachment data;
            ContentDisposition disposition;
            for (int i = 0; i < path.Length; i++)
            {
                data = new Attachment(path[i], MediaTypeNames.Application.Octet);//实例化附件  
                disposition = data.ContentDisposition;
                disposition.CreationDate = System.IO.File.GetCreationTime(path[i]);//获取附件的创建日期  
                disposition.ModificationDate = System.IO.File.GetLastWriteTime(path[i]);//获取附件的修改日期  
                disposition.ReadDate = System.IO.File.GetLastAccessTime(path[i]);//获取附件的读取日期  
                mailMessage.Attachments.Add(data);//添加到附件中  
            }
        }
        /// <summary>  
        /// 异步发送邮件  
        /// </summary>  
        /// <param name="CompletedMethod"></param>  
        public void SendAsync(SendCompletedEventHandler CompletedMethod)
        {
            if (mailMessage != null)
            {
                smtpClient = new SmtpClient();
                smtpClient.Credentials = new System.Net.NetworkCredential(mailMessage.From.Address, password);//设置发件人身份的票据  
                smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                smtpClient.Host = "smtp." + mailMessage.From.Host;
                smtpClient.SendCompleted += new SendCompletedEventHandler(CompletedMethod);//注册异步发送邮件完成时的事件  
                smtpClient.SendAsync(mailMessage, mailMessage.Body);
            }
        }
        /// <summary>  
        /// 发送邮件  
        /// </summary>  
        public void Send()
        {
            if (mailMessage != null)
            {
                using (smtpClient = new SmtpClient())
                {
                    smtpClient.Timeout = 9999999;
                    smtpClient.Credentials = new System.Net.NetworkCredential(mailMessage.From.Address, password);//设置发件人身份的票据  
                    smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                    smtpClient.Host = "smtp." + mailMessage.From.Host;
                    smtpClient.Send(mailMessage);
                    mailMessage.Attachments.Dispose();
                }
            }
        }
    }
}