Question

I am setting up a subscription service to send reports to various people in our company on a schedule. I plan to email the reports, the reporting system I am using is able to export as PDF stream (rather than writing temp files). Most people will receive more than one report so I am trying to attach them all to one email doing something like

List<Stream> reports = new List<Stream>();
//looping code for each users set of reports
Stream stream = ReportSource.ReportDocument.ExportToStream(PortableDocFormat)
reports.Add(stream);
stream.Flush();  //unsure
stream.Close();  //unsure
//end looping code

SmtpClient smtpClient = new SmtpClient(host, port);
MailMessage message = new MailMessage(from, to, subject, body);

foreach (Stream report in reports)
{
    message.Attachments.Add(new Attachment(report, "application/pdf"));
}                
smtpClient.Send(message);

What I am unsure about is should I be flushing and closing the stream just after adding it to the list will this be ok? Or do I need to loop the List afterwards to flush and dispose? I am trying to avoid any memory leak that is possible.

Answer 1

Why not create a StreamCollection class that implements IDisposable:

public class StreamCollection : Collection<Stream>, IDisposable { }

In the Dispose method of that class, you could loop through all of the streams and properly Close/Dispose of each stream. Then your code would look like:

using (var reports = new StreamCollection())
{
   //looping code for each users set of reports
   reports.Add(ReportSource.ReportDocument.ExportToStream(PortableDocFormat));
   //end looping codeSmtpClient 

   smtpClient = new SmtpClient(host, port);
   MailMessage message = new MailMessage(from, to, subject, body);

   foreach (Stream report in reports)
   {    
      message.Attachments.Add(new Attachment(report, "application/pdf"));
   }

   smtpClient.Send(message);
}