Defining == operator on WinRT class

Question

Why is there a restriction on defining the == operator on my custom WinRT classes? I get a compile time error saying that the  operator is not allowed.

Answer 1

Do you have some code you can share?  I can define that operator!

---

Jeff Sanders (MSFT)

@jsandersrocks - Windows Store Developer Solutions @WSDevSol
Getting Started With Windows Azure Mobile Services development? Click here
Getting Started With Windows Phone or Store app development? Click here
My Team Blog: Windows Store & Phone Developer Solutions
My Blog: Http Client Protocol Issues (and other fun stuff I support)

Answer 2

Hi Jim,

I assume you're running into C2919 here ("Operators cannot be used on the published surface of a WinRT type").

The published surface of the type has to be ABI compliant and representable via COM so it can be projected into all languages. I believe built-in Windows Runtime Classes which appear to override operators actually do so at the projection level rather than in the runtime class itself.

You can override operator== for use within the class by marking it protected or internal.

--Rob

Answer 3

Thanks Rob,

Yes that's the error message I'm getting back. Unfortunately I need the comparison outside of the class, so I'll have to address the problem by some other means.

Answer 4

You can provide an explicit comparison function (e.g. String::CompareOrdinal ).

--Rob