asp.net中发送邮件

protected void Button1_Click(object sender, EventArgs e)
{
string to, body, subject;
to = TextBox1.Text;//要发送的邮箱
subject = TextBox2.Text;//邮件主题
body = TextBox2.Text;//邮件内容
try
{
int nContain = 0;
///添加发件人地址
string from = "642122542@qq.com";
MailMessage mailMsg = new MailMessage();
mailMsg.From = new MailAddress(from);
nContain += mailMsg.From.Address.Length;
///添加收件人地址
mailMsg.To.Add(to);
nContain += mailMsg.To.ToString().Length;
///添加邮件主题
mailMsg.Subject = subject;
mailMsg.SubjectEncoding = Encoding.UTF8;
nContain += mailMsg.Subject.Length;
///添加邮件内容
mailMsg.Body = body;
mailMsg.BodyEncoding = Encoding.UTF8;
mailMsg.IsBodyHtml = true;
nContain += mailMsg.Body.Length;
if (mailMsg.IsBodyHtml == true)
{
nContain += 100;
}
///发送邮件
try
{
//定义发送邮件的Client
SmtpClient client = new SmtpClient();
//表示以当前登录用户的默认凭据进行身份验证　
client.UseDefaultCredentials = true;
//包含用户名和密码　
client.Credentials = new System.Net.NetworkCredential("642122542@qq.com", "密码");
///设置邮件服务器主机的IP地址
client.Host = "smtp.QQ.com";//163的服务器是 smtp.163.com
///设置邮件服务器的端口
client.Port = 25;
///配置发送邮件的属性
client.DeliveryMethod = SmtpDeliveryMethod.Network;
//System.Net.Mail.MailMessage　message　=　new　System.Net.Mail.MailMessage(strFrom,　strto,　strSubject,　strBody);　
mailMsg.Priority = System.Net.Mail.MailPriority.Normal;
//client.UseDefaultCredentials　=　false;
///发送邮件
client.Send(mailMsg);

}
catch (Exception ex) { throw ex; }
}
catch (Exception ex) { throw ex; }

}