default.cs

    //region 发送邮件
    static public void sendmail(string sendto, string subject, string body)
    {
　　// **** 代表邮件服务器
        smtpclient client = new smtpclient("******");
        client.usedefaultcredentials = true;
　　// 此处是用户名和密码
        client.credentials = new networkcredential("zhangbaozz", "123456");
        client.deliverymethod = smtpdeliverymethod.network;
　　// 邮箱
        mailmessage message = new mailmessage(zhangbaozz@***.com, sendto, subject, body);
        message.bodyencoding = encoding.getencoding("gb2312");
        message.isbodyhtml = true;
        try
        {
            client.send(message);
            return;
        }
        catch { return; }
    }
    //endregion

呵呵～ 顺便把asp的也一起发了吧....asp的要安装jmail组件

<%
sub jmail_new(email,topic,mailbody,rename,remail)
email  发送的邮件地址
topic 标题
mailbody 邮件主要内容
rename  回复人姓名
remail回复的邮件地址

 on error resume next
 dim jmail
 set jmail=server.createobject("jmail.message")
 jmail.logging=true
 jmail.charset="gb2312"
 jmail.mailserverusername = "****@****.com" 您的邮件服务器登录名
 jmail.mailserverpassword = "****" 登录密码 
 jmail.priority = 1

 =========这两个属性低版本的不支持
 jmail.sendername=rename
 发送者邮件地址
 jmail.sender = remail
 自动回复地址
 ===============
 
 jmail.replyto=remail 
 jmail.from="*****"
 jmail.fromname =rename 
 jmail.addrecipient email
 jmail.subject=topic
 jmail.htmlbody=mailbody
 jmail.body=""
 jmail.send ("mail.gkong.com")
 set jmail=nothing
 sendmail="ok"
 if err then
   sendmail="false"  
   response.write sendmail
 end if
end sub
%>