Strange “type of”

[kingtu]

I have a piece of code, as shown in the figure below.

Why isbill is “false” ？
If the type of c is form, the above situation will occur; Not if the type of c is control.

[pricerc]

If you look through the issues in this repo, you will find a few discussions about TypeOf, and how its behaviour is not always what people expect.

[rskar-git]

@kingtu

Could this be an issue about the debugger and the Watch window? I would suggest using the Quick Watch and the Immediate windows, and see what they display for TypeOf c Is IBill and isBill. You can also use them to confirm that c actually contains a reference to some object which implements IBill.

I suspect that the TypeOf operator is working as it should, but that the Watch window might not be getting properly updated (and hence making TypeOf c Is IBill and isBill seem out of sync).

[AnthonyDGreen]

Is this... using the full-width keywords of legend?