Code analysis complains I'm not disposing objects. What is wrong here?

Consider this code

private MailMessage GetMailMessageFromMailItem(Data.SystemX.MailItem mailItem)
        {

            var msg = new MailMessage();

            foreach (var recipient in mailItem.MailRecipients)
            {
开发者_运维百科                var recipientX = Membership.GetUser(recipient.UserKey);
                if (recipientX == null)
                {
                    continue;
                }

                msg.To.Add(new MailAddress(recipientX.Email, recipientX.UserName));
            }

            msg.From = new MailAddress(ConfigurationManager.AppSettings["EmailSender"],
                                   ConfigurationManager.AppSettings["EmailSenderName"]);

            msg.Subject = sender.UserName;
            if (!string.IsNullOrEmpty(alias)) msg.Subject += "(" + alias + ")";
            msg.Subject += " " + mailItem.Subject;
            msg.Body = mailItem.Body;
            msg.Body += Environment.NewLine + Environment.NewLine + "To reply via Web click link below:" + Environment.NewLine;
            msg.Body += ConfigurationManager.AppSettings["MailPagePath"] + "?AID=" + ContextManager.AccountId + "&RUN=" + sender.UserName;

            if (mailItem.MailAttachments != null)
            {
                foreach (var attachment in mailItem.MailAttachments)
                {
                    msg.Attachments.Add(new Attachment(new MemoryStream(attachment.Data), attachment.Name));
                }
            }

            return msg;
        }

I'm just taking my database type and converting to MailMessage. It get's sent in another function.

Code analysis tells me I'm not disposing "msg" which is correct. But if I do it here - I get exception when I'm trying to send it.

Also, it complains about not disposing MemoryStream here:

msg.Attachments.Add(new Attachment(new MemoryStream(attachment.Data), attachment.Name));

I have no idea on how to properly dispose it. I tried different things but was getting exceptions when sending mail saying "Stream is closes"

Basically you shouldn't - disposing of the mail message later will dispose of each attachment, which will dispose of each stream. Besides, failing to dispose of a MemoryStream which isn't being used in remoting won't do any harm.

I suggest you suppress the warning for this method.

EDIT: I suspect you can use [SuppressMessage] to suppress the message.

Note that there's a risk that some code will throw code half way through the method, so you end up never being able to dispose of the message even if you have a using statement in the calling code. If you're really bothered, you could write:

private MailMessage GetMailMessageFromMailItem(Data.SystemX.MailItem mailItem)
{
    bool success = false;
    var msg = new MailMessage();
    try
    {
        // Code to build up bits of the message
        success = true;
        return msg;
    }
    finally
    {
        if (!success)
        {
            msg.Dispose();
        }
    }
}

Personally I'd say this is overkill though.

With regards to "not disposing "msg"", the only way I can think of is instead of returning MailMessage rather pass in a reference to a MailMessage. Something like this. Not sure if it's such a good idea.

private void GetMailMessageFromMailItem(ref MailMessage msg, Data.SystemX.MailItem mailItem)

The creator of the disposable object should also dispose it. If you can't dispose the message here then it should be passed in from a creator somewhere else. Code analysis is right in this case and you can end up with very unfortunate and hard to debug leaks if you ignore these messages.