Does we need the capablity of building ActiveX server(CVI)?

[jacky Wang]

I have to admit that this is not a good question. But I still can not help asking this question, because as far as I know, the function could be totally replaced by DLL when we program. ActiveX is derived from COM and kind of improvements over traditional DLL, such as avoiding DLL hell . But does it really take advantage since its programming could take more time compared with DLL.? From the view of a test engineer, I never see the advantage of this technology in practice.

Thanks
Jacky

[jr_2005]

While I agree that ActiveX can be troublesome to use, and I try to avoid it if at all possible, you cannot escape the scenario that a third party supplier (eg Microsoft) might produce a programming interface to their code (eg Excel) only in ActiveX. Then, you have to use it. (Imagine trying to access an Excel spreadsheet just by calling directly into the dlls - makes me shiver just thinking about it. )

So, even if you don't use it for your own code, it is worth keeping the knowledge of how to use ActiveX, just in case...

JR

Message Edited by jr_2005 on 12-05-2006 03:32 PM

[menchar]

ActiveX and COM are chunks of binary reusability.  And they are objects with interfaces but they don't support inheritance.

In the CVI framework you have the ability to access source or binaries (linked statically (library) or dynamically (DLL) and the need for binary reusability isn't there very often.

But as jr said, vendors who want to deploy chunks of resuable software but don't want to expose source or relinkable binaries often choose to deploy COM objects.  More flexible than simply distributing executables, but still fairly constrained.  ActiveX was pitched by Micro$oft to vendors as a way to sell reusable collections of software chunks.

And I gotta say that most COM/ActiveX objects that use a GUI have a different look and feel to the GUI that's discordant with the NI look and feel.  It can make for a bit of weirdness.

I think CVI 8.0 uses some Activex objects in the IDE - the distribution management panel has that small, inflexible, weird ActiveX look to it.  I just love scrolling through the tiny windows that never show you everything at once and can't be resized.