如何使用dotnetnuke发送电子邮件？

string smtpServer = "mail.occtbangalore.org";
string smtpAuthentication = (string)Globals.HostSettings["SMTPAuthentication"];
string smtpUsername = (string)Globals.HostSettings["SMTPUsername"]; 
string smtpPassword = (string)Globals.HostSettings["SMTPPassword"];

MailMessage mail = new MailMessage();

mail.From = new MailAddress("[email protected]);
mail.To.Add(txtEmail.Text.Trim());
mail.Subject = "OCCT BANGALORE";
string html = "<img src=\"cid:Logo\" />";
AlternateView av2 = AlternateView.CreateAlternateViewFromString(html,null,text/html");   
string logoFile = MapPath(PortalSettings.HomeDirectory + PortalSettings.LogoFile);
if (File.Exists(logoFile))
{
     LinkedResource linkedResource = new LinkedResource(logoFile);
     linkedResource.ContentId = "Logo";
     linkedResource.ContentType.Name = logoFile;
     linkedResource.ContentType.MediaType = "image/jpeg";
     av2.LinkedResources.Add(linkedResource);
}
mail.AlternateViews.Add(av2);
SmtpClient emailClient = new SmtpClient(smtpServer);
if (smtpAuthentication == "1")
{
    NetworkCredential SMTPUserInfo = new NetworkCredential(smtpUsername,smtpPassword);    
    emailClient.UseDefaultCredentials = false;
    emailClient.Credentials = SMTPUserInfo;
}
emailClient.Send(mail);
string smtpServer = "mail.occtbangalore.org";
s