>John,
>
>In the Guest Opinion column in the Dec. 99 Visual Basic Programmer's Journal (yes, I read it...I've subscribed for a couple of years), the author says something that I'm trying to apply to what you said regarding implements and also to how COM is implemented in VFP. I'm hoping you can shed some light on it. Here's what the author says:
>
>
"For example, we'd like more control over the generation of interface IDs. The limited control VB currently provides actually discourages you from using VB to build components for large-scale applications. This is because even trivial changes to your components result in time-consuming recompiles and related headaches. VB developers building large-scale applications also need the ability to implement interfaces derived from custom interfaces other than IUnknown and IDispatch. Working around this limitation often requires major and unnecessary redesign work for component behavior. It would also be nice if VB7 were to give us more control over internal COM interfaces such as IClassFactory. VB developers don't really want to hack these interfaces; we just want more control over our objects.">
>So, back to my question. How does this apply to VB's Implements? What will adding additional interfaces other than IUnknown and IDispatch give to VB developers? And, finally, how does this apply to VFP COM Objects?
Part of this sounds kinda bogus to me. All COM objects have to support IUnknown and most of them support IDispatch (otherwise one has to use VTable binding). But the interface one creates in his own COM objects are neither IUnknown nor IDispatch. Our custom interfaces also support those two interfaces, but the actual interface we create with new methods (and what looks like properties) is a new interface all by itself.
VFP seems to do a fairly good job as far as the IDs go. It only recreates them when told to do so.
With COM+, being able to implement different interfaces becomes a major issue. MS hasn't made any announcements yet, but I assume VB as well as VFP will be able to participate in COM+/ WinDNA environments.
Markus
