Add ThrowExceptions property

[Ron]

Sometimes its cumbersome to deal with errors:

// warning: FromAddress missing!
EmailMessage emailMessage = null;
try
{
  emailMessage = new EmailMessage();
  if (emailMessage.Send(smtp) == false)
  {
   log.Error("Unable to send mail.");
  }
}
catch (MailException ex)
{
  StringBuilder sb = new StringBuilder("Unable to send mail.");
  if (emailMessage != null)
  {
   sb.Append(Environment.NewLine);
   sb.Append(emailMessage.ToDataString());
  }
  log.Error(sb.ToString(), ex);
}
catch (Exception ex)
{
  if (emailMessage != null)
  {
   log.Error("Unable to send mail: " + emailMessage.ToDataString(), ex);
  }
  else
  {
   log.Error("Unable to send mail.", ex);
  }
}

If the EmailMessage object had a property indicating whether or not it should swallow its own exceptions it would be easier to extract this information later:

// warning: FromAddress missing!
EmailMessage emailMessage = new EmailMessage();
emailMessage.ThrowExceptions = false;
if (emailMessage.Send(smtp) == false)
{
log.Error(
  "Unable to send mail."+emailMessage.ToDataString(),
  emailMessage.GetLastException());
}

You would always have access to a non-null EmailMessage object that you could investigate and log if the email was not send successfully.

[Mike Bridge]

One of my beefs about C# is that it the compiler doesn't force you to acknowledge potential exceptions, making it dangerous to use anything outside of a try-catch block.  I feel it's a violation of the calling contract, and it means that unless you really trust the documentation and love to read it, you need to do one catch-all block somewhere with a "catch (Exception ex)". 

That said, my philosophy is that an exception should be thrown for abnormal behaviour (e.g. there is a network error, a problem with the SMTP server, etc.), and I generally leave it up to the caller to catch it.  It certainly makes for nicer error-handling code in the module.  But that's my personal preference....

[Ron]

This was the case that made me suggest the idea:

EmailMessage emailMessage = null;
try
{
emailMessage = new EmailMessage();
emailMessage.AddToAddress(new DotNetOpenMail.EmailAddress(toEmail));
// emailMessage.FromAddress = new DotNetOpenMail.EmailAddress(fromEmail);
emailMessage.Subject = subject;
emailMessage.TextPart = new TextAttachment(textBody);
emailMessage.Send(smtpServer);
}
catch (MailException ex)
{
if (emailMessage != null)
{
  emailLog.Info(emailMessage.ToDataString(), ex);
}
}
catch (Exception ex)
{
emailLog.Error("Unable to send mail.", ex);
}

[NullReferenceException: Object reference not set to an instance of an object.] 

DotNetOpenMail.EmailMessage.GetStandardHeaders(Encoding charset, IEncoder encoder) +46  

DotNetOpenMail.EmailMessage.ToDataStringHeaders(Encoding charset, IEncoder encoder) +44

DotNetOpenMail.EmailMessage.ToDataString() +27

If emailMessage is not null how do I know if its safe to call ToDataString()?

[Mike Bridge]

If it's throwing a null pointer exception, that'd be a bug---I'll look at that.  Hence my distaste for the looseness of the C# Exception handling. :)

-Mike

P.S. Technically, my ToDataString() method should have an "internal" declaration, but because my NUnit testing code is in a separate Project, I made it public.