Catagory Cannot be found

Question

I'm having an issue that if a user enters a none existing catagory or typing error, and that catagory is not listed it causes the application to crash. I've narrowed it down to this particular piece of code but want to know what type of condition I can use that if the instance "key" cannot be found to throw an exemption.

This is what I have so far...

myDecryptor.DomainKey key = myDecryptor.DomainKey.Instance[dmCategory.ToLower()]

//what I've added

if (key) //looking for a condition that would throw this exception if key is not found

{

throw new Exception();

}

Vulpes · Answer

If it's something that the user needs to know and may be able to do something about then instead of throwing an exception you could pop up a MessageBox to tell the user what the problem is and give him/her the option to exit the program immediately. Otherwise if it's not a fatal error you could just continue with the program after taking any remedial action. Personally I HATE throwing exceptions and always try to continue the program or at the very least make a graceful exit.

Marc · Answer

I don't like doing it either but I might just log the error and try to continue the program. Have to rethink it. Thanks!

Marc · Answer

Vulpes it is a custom class. It's actually a .dll file that I had to create and instance of to walk through it. The method called in this class cycles through all the known domains and then is null if it doesn't match any of the domains. I tried to insert the if(key ==null) and the exception is thrown but is there a way I can continue executing the method without allowing the exception to stop the program even through the key maybe null?

Vulpes · Answer

Well it's not a .NET framework class so I can't look it up. But I'd guess that the Instance indexer returns null if it can't find the key. So I'd try: if (key == null) { throw new Exception(); }