How can an object not be compared to null?

Question

I have an \'optional\' parameter on a method that is a KeyValuePair. I wanted an overload that passes null to the core method for this parameter, but in the core method, wh

Answer 1

KeyValuePair is a struct, not a class. It's like doing:

int i = 10;
if (i != null) ...

(Although that is actually legal, with a warning, due to odd nullable conversion rules. The important bit is that the if condition will never be true.)

To make it "optional", you can use the nullable form:

static void Foo(KeyValuePair? pair)
{
    if (pair != null)
    {
    }
    // Other code
}

Note the ? in KeyValuePair?