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Null parameter checking in C#

Asked 2011-09-28T15:19:32.023
91

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 that uses s will throw an exception anyway. And such checks make code slower and harder to maintain.

void f(SomeType s)
{
  if (s == null)
  {
    throw new ArgumentNullException("s cannot be null.");
  }

  // Use s
}
c# function null
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The main benefit is that you're being explicit with the requirements of your method right from the start. This makes it clear to other developers working on the code that it is truly an error for a caller to send a null value to your method.

The check will also halt the execution of the method before any other code executes. That means you won't have to worry about modifications being made by the method that are left unfinished.

answered 2011-09-28T15:21:47.733

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