using
                 System;

                using
                 System.Collections.Generic;

                using
                 System.Linq;

                using
                 System.Web;

                using
                 System.Web.UI;

                using
                 System.Web.UI.WebControls;

                using System.Net;          //互联网命名空间using System.Net.Mail;     //互联网下的邮件命名空间publicpartialclass _Default : System.Web.UI.Page
{
    protectedvoid Page_Load(object sender, EventArgs e)
    {
        Button1.Click += Button1_Click;
    }

    void Button1_Click(object sender, EventArgs e)
    {
        string to = TextBox1.Text; //接收者邮箱地址string title = TextBox2.Text; //邮件标题string content = TextBox3.Text; //邮件内容


        //创建新浪邮箱服务器对象
        SmtpClient smtp = new SmtpClient("smtp.sina.cn");
        smtp.EnableSsl = true;
        smtp.UseDefaultCredentials = false;


        //发送者是谁
        MailAddress fr = new MailAddress("1856*****@sina.cn");

        //接收者是谁
        MailAddress t = new MailAddress(to);


        //发送的邮件对象
        MailMessage mail = new MailMessage(fr, t);


        //给邮件对象标题属性赋值
        mail.Subject = title;
       // mail.Subject = "[奇点网络]邮箱验证邮件";

        //给邮件对象内容属性赋值
        mail.Body = content;
       // mail.Body = "欢迎注册奇点网络平台，您的邮箱验证码为[drtr]，请在20分钟内填写，系统邮件请勿回复！";
        //mail.Body = "yanzheng.qidian.com?i=kjwehrlkydafghdjfghwerkwehr";


        //创建证书对象
        NetworkCredential cred = new NetworkCredential("185********@sina.cn", "hq1234561");


        //设置资格证书
        smtp.Credentials = cred;


        //发送        smtp.Send(mail);

    }
}