c# 发邮件

using system;
using system.collections.generic;
using system.text;
using system.configuration;
using system.io;
using system.web;
using system.net.mail;
using system.net;
using system.componentmodel;

namespace easyframe.common
{
    public class gtmail
    {
        #region 发送电子邮件
        /// <summary>
        /// 发送电子邮件
        /// </summary>
        /// <param name="smtpserver">smtp服务器</param>
        /// <param name="username">登录帐号</param>
        /// <param name="pwd">登录密码</param>
        /// <param name="nickname">发件人昵称</param>
        /// <param name="strfrom">发件人</param>
        /// <param name="strto">收件人</param>
        /// <param name="subj">主题</param>
        /// <param name="bodys">内容</param>
        public static void sendmail(string smtpserver, string username, string pwd, string nickname, string strfrom, string strto, string subj, string bodys)
        {
            smtpclient _smtpclient = new smtpclient();
            _smtpclient.deliverymethod = smtpdeliverymethod.network;//指定电子邮件发送方式
            _smtpclient.host = smtpserver;//指定smtp服务器
            _smtpclient.credentials = new system.net.networkcredential(username, pwd);//用户名和密码

            //mailmessage _mailmessage = new mailmessage(strfrom, strto);
            mailaddress _from = new mailaddress(strfrom, nickname);
            mailaddress _to = new mailaddress(strto);
            mailmessage _mailmessage = new mailmessage(_from, _to);
            _mailmessage.subject = subj;//主题
            _mailmessage.body = bodys;//内容
            _mailmessage.bodyencoding = system.text.encoding.default;//正文编码
            _mailmessage.isbodyhtml = true;//设置为html格式
            _mailmessage.priority = mailpriority.normal;//优先级
            _smtpclient.send(_mailmessage);
        }
        #endregion

        #region 简单电子邮件发送
        /// <summary>
        /// 简单电子邮件发送
        /// </summary>
        /// <param name="smtpserver">smtp服务器</param>
        /// <param name="username">登录帐号</param>
        /// <param name="pwd">登录密码</param>
        /// <param name="nickname">发件人昵称</param>
        /// <param name="mailfrom">发件人</param>
        /// <param name="mailto">收件人</param>
        /// <param name="subj">主题</param>
        /// <param name="bodys">内容</param>
        public static void sendmail(string smtpserver, int smtpport, string username, string pwd, string nickname, string mailfrom, string mailto, string subj, string bodys)
        {
            smtpclient _smtpclient = new smtpclient();
            _smtpclient.deliverymethod = smtpdeliverymethod.network;//指定电子邮件发送方式
            _smtpclient.host = smtpserver;//指定smtp服务器
            _smtpclient.port = smtpport;
            _smtpclient.enablessl = true;
            //_smtpclient.sendcompleted += new sendcompletedeventhandler(smtp_sendcompleted);
            _smtpclient.credentials = new networkcredential(username, pwd);//用户名和密码    
            mailaddress _from = new mailaddress(mailfrom, nickname, encoding.getencoding(936));
            mailaddress _to = new mailaddress(mailto);
            mailmessage _mailmessage = new mailmessage(_from, _to);
            _mailmessage.subject = subj;//主题
            _mailmessage.body = bodys;//内容
            _mailmessage.bodyencoding = encoding.default;//正文编码
            _mailmessage.isbodyhtml = true;//设置为html格式
            _mailmessage.priority = mailpriority.normal;//优先级
            _smtpclient.send(_mailmessage);
            //_smtpclient.sendmailasync(_mailmessage);
        }

        private static void smtp_sendcompleted(object sender, asynccompletedeventargs e)
        {
            string msg = e.userstate.tostring();
            smtpclient smtp = (smtpclient)sender;
            if (e.error == null)//问题出现后，这里的error并没有错误
            {
                msg += ",1";//发送成功
            }
            else
            {
                msg += ",0";
                smtp.sendasynccancel();
            }
        }
        #endregion

        #region 邮件批量发送
        /// <summary>
        /// 邮件批量发送
        /// </summary>
        /// <param name="smtpserver"></param>
        /// <param name="smtpport"></param>
        /// <param name="username"></param>
        /// <param name="pwd"></param>
        /// <param name="mailfrom"></param>
        /// <param name="nickname"></param>
        /// <param name="mailto"></param>
        /// <param name="subj"></param>
        /// <param name="bodys"></param>
        /// <param name="cc"></param>
        /// <param name="bcc"></param>
        /// <param name="mailattachments"></param>
        public static void sendmail(string smtpserver, int smtpport, string username, string pwd, string mailfrom, string nickname, string[] mailto, string subj, string bodys, string[] cc, string[] bcc, string[] mailattachments)
        {
            smtpclient smtp = new smtpclient(); //实例化一个smtpclient
            smtp.deliverymethod = smtpdeliverymethod.network; //将smtp的出站方式设为 network
            smtp.enablessl = false;//smtp服务器是否启用ssl加密
            smtp.host = smtpserver; //指定 smtp 服务器地址
            smtp.port = smtpport;             //指定 smtp 服务器的端口，默认是25，如果采用默认端口，可省去
                                              //如果你的smtp服务器不需要身份认证，则使用下面的方式，不过，目前基本没有不需要认证的了
            smtp.usedefaultcredentials = true;
            //smtp.sendcompleted += new sendcompletedeventhandler(smtp_sendcompleted);
            //如果需要认证，则用下面的方式
            smtp.credentials = new networkcredential(username, pwd);
            mailmessage mm = new mailmessage(); //实例化一个邮件类
            mm.priority = mailpriority.normal; //邮件的优先级，分为 low, normal, high，通常用 normal即可
            mm.from = new mailaddress(mailfrom, nickname, encoding.getencoding(936));
            //收件方看到的邮件来源；
            //第一个参数是发信人邮件地址
            //第二参数是发信人显示的名称
            //第三个参数是 第二个参数所使用的编码，如果指定不正确，则对方收到后显示乱码
            //936是简体中文的codepage值
            //注：上面的邮件来源，一定要和你登录邮箱的帐号一致，否则会认证失败

            mm.replytolist.add(mailfrom);
            //replyto 表示对方回复邮件时默认的接收地址，即：你用一个邮箱发信，但却用另一个来收信

            if (cc.length > 0)
            {
                mm.cc.add(string.join(",", cc));//抄送  
            }
            if (bcc.length > 0)
            {
                mm.bcc.add(string.join(",", bcc));//密送
            }
            if (mailattachments.length > 0)
            {
                for (int i = 0; i < mailattachments.length; i++)
                {
                    attachment objmailattachment = new attachment(@mailattachments[i]);//发送邮件的附件的地址
                    mm.attachments.add(objmailattachment);//将附件附加到邮件消息对象中 
                }
            }
            mm.to.add(string.join(",", mailto));
            mm.subject = subj; //邮件标题
            mm.subjectencoding = encoding.getencoding(936);
            // 这里非常重要，如果你的邮件标题包含中文，这里一定要指定，否则对方收到的极有可能是乱码。
            // 936是简体中文的pagecode，如果是英文标题，这句可以忽略不用
            mm.isbodyhtml = true; //邮件正文是否是html格式

            mm.bodyencoding = encoding.getencoding(936);
            //邮件正文的编码， 设置不正确， 接收者会收到乱码

            mm.body = bodys;
            //邮件正文
            smtp.send(mm);
            //smtp.sendmailasync(mm); //发送邮件，如果不返回异常， 则大功告成了。
        }
        #endregion 
    }
}