Question

I am trying to write operator overload for custom class and don’t know how to handle null comparison.

Class Customer {     int id;      public static bool operator ==(Customer a, Customer b)     {         //When both a and b are null don't know how to compare as can't use == in here as         //it will fall into loop     } } 

Problem is when a and b both are null result is true but not sure how to check it without using ==.

Answer 1

if (Object.ReferenceEquals(a,b))      return true; 

ReferenceEquals() checks if they are pointing to the exact same object (or if they are both null)

(As a general rule, it’s good to start an Equals() method with a call to ReferenceEquals, particularly if the rest of the method is complicated. It will make things like a==a quickly return true, instead of having to check every element.)