Re: Casting null to nullable

On 11/15/07, Rich Armstrong <[email protected]> wrote:
>
> I'm aware of one situation that requires an explicit cast:
>
>    // This produces an error "Type of conditional expression
>    // cannot be determined because there is no implicit conversion
>    // between 'int' and '<null>'"
>    int? nullableInt = someCondition ? 0 : null;
>
>    // This compiles without error
>    int? nullableInt = someCondition ? 0 : (int?)null;


I'll bet you can also say
int? nullableInt = someCondition ? (int?)0 : null

The compiler has to be able to find a common type between "0" and "null" in
order to generate code, and apparently it doesn't in this case.  The fact
that the variable declaration is "int?" is a bit of a red herring as the
type of the lhs of the expression is not taken into account when evaluating
the rhs.

--
Curt Hagenlocher
[email protected]

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