Null parameter checking in C#

Question

In C#, are there any good reasons (other than a better error message) for adding parameter null checks to every function where null is not a valid value? Obviously, the code tha

Answer 1

Without an explicit if check, it can be very difficult to figure out what was null if you don't own the code.

If you get a NullReferenceException from deep inside a library without source code, you're likely to have a lot of trouble figuring out what you did wrong.

These if checks will not make your code noticeably slower.

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Note that the parameter to the ArgumentNullException constructor is a parameter name, not a message.
Your code should be

if (s == null) throw new ArgumentNullException("s");

I wrote a code snippet to make this easier:

    
        

            
            tna
            Code snippet for throw new ArgumentNullException
            SLaks
            
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                    Parameter
                    Paremeter to check for null
                    value