I don't deal with these kind of technical questions anymore. I have been developing full time now for 5 years and I have been building websites since the mid 90's. If I didn't know what I was doing, I wouldn't still be working.

If you are looking for an entry level programmer, then fine. Ask them some technical questions, but don't expect them to know everything, and don't hold it against them. After all, that's why they are entry level positions, and you are going to be asking your senior staff to train them.

Any position higher than entry level and you are wasting your time, and if you are looking to fill a senior level position, asking someone to explain what a namespace is, or the difference between boxing and unboxing, is just plain insulting.

On my resume I have listed my educational background, my work experience, and all the languages and applications I have proficiency in (and the level of that proficiency). A potential employer has everything they need to determine my knowledge and experience.

If someone wants to ask about my approach to software design and engineering, I am happy to discuss it. If they start asking questions like the ones above that are designed to test my knowledge, then they are basically telling me they think I am lying on my resume, and that is not the way to start an employer/employee relationship.

If I was heading an IT department and looking to staff it, I would make sure my senior staff have a certain level of experience, but also that they would be people who, if they didn't know the answer right away, they would know how to go and find the answer.

On every project, application, or task I have worked on, I and my colleagues inevitably run into a programming challenge that we don't have the anwer to off the top of our heads. That's what the internet/MSDN/Google is for.

Software development is about problem solving. Similarly, developing a software application boils down to problem solving. We're not taking a quiz. We're not trying to see how many technical details we can cram into our heads to impress people. The goal is to use every resource available to design and create the best application we can to solve our client's problem.