.Net自带的MailMessage类不支持验证。用CDO吧
Using CDO;onfiguration conf=new ConfigurationClass();
conf.Fields[CdoConfiguration.cdoSendUsingMethod].Value
=CdoSendUsing.cdoSendUsingPort;
conf.Fields[CdoConfiguration.cdoSendEmailAddress].Value="[email protected]";
conf.Fields[CdoConfiguration.cdoSendPassword].Value="******";
conf.Fields[CdoConfiguration.cdoSMTPServer].Value="smtp.xxx.xxx";
conf.Fields[CdoConfiguration.cdoSendUserName].Value="[email protected]";
//发送者名称,这一项要注意检查,不可以乱写
conf.Fields[CdoConfiguration.cdoSMTPServerPort].Value=25;
conf.Fields[CdoConfiguration.cdoSMTPAuthenticate].Value
=CdoProtocolsAuthentication.cdoBasic;
conf.Fields.Update();

MessageClass mail=new MessageClass();
mail.TextBody=txtBody.Text;
mail.Configuration=conf;
mail.To=txtRcv.Text;
mail.From="[email protected]";
mail.Subject=txtTitle.Text;
mail.CC=txtCC.Text;
mail.BCC=txtBCC.Text;
string strPath=Cache["Path"].ToString();
mail.AddAttachment(strPath,"wacle","storm");//添加附件功能
try
{
mail.Send();
Response.Write("<script language='javascript'>alert('邮件发送成功')</script>");
}
catch
{
Response.Write("<script language='javascript'>alert('邮件发送失败')</script>");
}