What is the cleanest way to see if a nullable type has a value, and if it does, to compare the value to another non nullable type's value?

I have two nullable enums which I would like to compare the value of to two regular enums. If the nullable enums do not have a value, I want the comparison to evaluate to true. This is what my logic looks like so far:

if (!nullableEnumOne.HasValue || nullableEnumOne.Value == regularEnumOne) 
    && (!nullableEnumTwo.HasValue || nullableEnumTwo.Value == regularEnumTwo)
    //do something

Is there a way to simplify this logic which I am missing?

Jon Skeet

It's probably simplest to use the null-coalescing operator to "default" to the value that you're comparing against:

if ((nullableEnumOne ?? regularEnumOne) == regularEnumOne &&
    (nullableEnumTwo ?? regularEnumTwo) == regularEnumTwo)

Or stick with your current code... or compare against null instead of using a negative condition:

if ((nullableEnumOne == null || nullableEnumOne.Value == regularEnumOne) 
    && ((nullableEnumTwo == null || nullableEnumTwo.Value == regularEnumTwo))

Or slightly weirdly, you could call Equals with the null conditional operator, using the null coalescing operator to make the null case true:

if ((nullableEnumOne?.Equals(regularEnumOne) ?? true)
   && (nullableEnumTwo?.Equals(regularEnumTwo) ?? true))

None of these are massively readable, admittedly. I'd be tempted to write a helper method, so you can write:

if (NullOrEqual(nullableEnumOne, regularEnumOne) &&
    NullOrEqual(nullableEnumTwo, regularEnumTwo))


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