c# - What is the difference between Nullable<T>.HasValue or Nullable<T> != null?

Question

I always used Nullable<>.HasValue because I liked the semantics. However, recently I was working on someone else's existing codebase where they used Nullable<> != null exclusively instead.

Is there a reason to use one over the other, or is it purely preference?

1. int? a;
   if (a.HasValue)
       // ...
   

vs.

2. int? b;
   if (b != null)
       // ...
   

Answer 1

The compiler replaces null comparisons with a call to HasValue, so there is no real difference. Just do whichever is more readable/makes more sense to you and your colleagues.