Overriding == operator. How to compare to null? [duplicate]

Answer 1

Cast the Person instance to object:

public static bool operator ==(Person person1, Person person2)
{
    if ((object)person1 == (object)person2) return true;
    if ((object)person1 == null) return false;
    if ((object)person2 == null) return false;
    return person1.Equals(person2);
}