引发和捕获异常＃2

Question

I've a console application that zips files and then send them via email. It does that every hour. I wanted to know what kind of exceptions should I handle ? Let say if there's no network available when the process starts. What exception will I get then ? And what can be the other ways this can fail. So basically I'm trying to figure out what exceptions I should catch.

I got something like this

try
{
    // zips files and send email
}      
catch(System.Net.Mail.SmtpException e)
{
    Console.WriteLine(e.toString());
}
catch(exception e)
{

}

Answer 1

Ideally, the libraries you're using will come with documentation that will list all of the types of exceptions that can be thrown, if not then you'll have to use a tool like Reflector to inspect the methods you're using to find their thrown exceptions.

For example, the SmtpClient.Send method (as documented here http://msdn.microsoft.com/en-us/library/swas0fwc.aspx ) lists these exceptions:

• ArgumentNullException
• InvalidOperationException
• ObjectDisposedException
• SmtpException
• SmtpFailedRecipientsException

Remember to catch exceptions in descending order of derivity, ie catch SmtpFailedRecipientsException before SmtpException because SmtpFailedRecipientsException derives from SmtpException .

Answer 2

You can review the MSDN pages to view what types of exceptions certain methods or constructors will throw from .NET libraries. Such as, for the SmtpClient.Send method , it throws the following exceptions:

• ArgumentNullException
• InvalidOperationException
• ObjectDisposedException
• SmtpException
• SmtpFailedRecipientsException

There is also a link of common exception types that you may be interested in located here .