C#发邮件的代码 (vs2005)

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net;
using System.Net.Mail;
public partial class sendemail : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {

        string s_from = TextBox1.Text.Trim().ToString();
        string s_to = TextBox3.Text.Trim().ToString();
        string pwd=TextBox2.Text .Trim().ToString();
        string s_body =TextBox5.Text.Trim().ToString();
        s_body = s_body.Replace("\r\n","<br/>");
        s_body = s_body.Replace("\n", "<br/>");
        s_body = s_body.Replace(" ", "&nbsp");

        int i = s_from.IndexOf("@");
        string username = s_from.Substring(0,i);

        MailAddress from = new MailAddress(s_from);
        MailAddress to = new MailAddress(s_to);
        MailMessage mailobj = new MailMessage(from ,to);
        mailobj.Subject = TextBox4.Text.Trim().ToString();
        mailobj.Body = s_body;
        mailobj.IsBodyHtml = true;
        mailobj.BodyEncoding = System.Text.Encoding.GetEncoding("GB2312");
        mailobj.Priority = MailPriority.High;

        if (FileUpload1.PostedFile.ContentLength > 0)
        {
            mailobj.Attachments.Add(new Attachment(  FileUpload1.PostedFile.FileName));
        }

        SmtpClient smtp = new SmtpClient("smtp.163.com");
       // smtp.Host = "smtp.163.com";
        smtp.UseDefaultCredentials = false;
        smtp.Credentials = new NetworkCredential(username,pwd);
        smtp.DeliveryMethod = SmtpDeliveryMethod.Network;

        try {
            smtp.Send(mailobj);
            Response.Write("ok!");
       
        }
        catch
       
        {
            Response.Write("sorry!");
        }
      
       
         }
}

////因为用的邮箱都是163的,所以就设置了smtp的地址是163的地址,如果用别的邮箱,只要smtp的地址改下就可以了.