When writing an operator==, it is common to want to check whether or not an operand is null or check if both operands refer to the same object. Attempting to do this using == will not work as it will simply call the overridden operator== that is being defined.

There are two suggested ways to fix the problem. The tidiest approach is to simply replace the call to operator== with a call to ReferenceEquals (see code below). As a less preferable alternative, it is also possible to simply cast the parameters to object .

In this example the == overload will constantly call itself to compare the initial arguments passed to it with null.

The best fix is to use the ReferenceEquals method instead.
  • Guidelines for Overloading Equals() and Operator== (C#)
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