/// <summary>
    /// 发送邮件找回密码
    /// </summary>
    /// <param name="toadd">目的地址</param>
    /// <param name="sb">内容</param>
    /// <param name="subject">主题</param>
    /// <returns></returns>
    public bool sendemail(string toadd, string sb, string subject)
    {
        try
        {
            //用于发送邮件的地址。 
            MailAddress from = new MailAddress("abc@www.com.cn");
            //目的地址
            MailAddress to = new MailAddress(toadd);
            MailMessage message = new MailMessage(from, to);
            //主题 
            message.Subject = subject;
            message.IsBodyHtml = true;
            //正文 
            message.Body = sb;
            //设置smtp服务器。 
            SmtpClient client = new SmtpClient("mail.www.com.cn");
            client.Credentials = new System.Net.NetworkCredential("user", "pass");//设置登录stmp服务器的用户名和密码，前面填帐号比如abc，后面的是该邮箱密码。 
            client.EnableSsl = true;
            client.Send(message);
            message.Dispose();
            return true;
        }
        catch (Exception e)
        {
            return false;
        }
    }