How can I manage the onslaught of null checks?

Question

Quite often, in programming we get situations where null checks show up in particularly large numbers. I'm talking about things like:

if (doc != null) {   if (doc.Element != null)   {     ... and so on   }   else     throw new Exception("Element cannot be null"); } else {   throw new Exception("document cannot be null"); } 

Basically, the whole thing turns into an unreadable nightmare, so I'm wondering: is there an easier way to describe what I'm trying to do above? (In addition to null checks, I get things like string.IsNullOrEmpty from time to time.)

Accepted answer: I accepted the answer that has this link because the approach described is innovative, and is precisely what I want. Thanks Shawn!

Answer 1

Check out this article: A fluent approach to C# parameter validation

It's written by one of the Paint.NET Developers. He uses extension methods to simplify and clean up null checking code.

Answer 2

Push them forward to the beginning of the function, and keep them out of the part of the code that does the work. Like this:

if (doc == null)     throw new ArgumentNullException("doc"); if (doc.Element == null)     throw new ArgumentException("Element cannot be null"); AndSoOn();