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(" ", " ");

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.