What is COM ???

[techman2553]

Hello,

I know what ActiveX controls are, and I have made a few, but what is COM, DCOM, COM+, etc. I never really bothered to look into this before, but seeing as how VBForums has an entire section devoted to this, I thought I'd ask.

Thanks

[razzaj]

well if you are familiar with ActiveX. COM are a bit like ActiveX

one difference you dont see them. They are not a button nor a fancy listbox.

They are rather a set of Classes. ( ihope you are familiar with OOP)

that contains functions and Properties.

This is roughly what they are. What they are used for, depends but mainly they are more like an archive of methods and functions either to perform Queries to a Database (fonr instance) without having to know the Connection String or how to make joins etc ...
and they contain all OOP concepts like inheritance etc ...

Another Thing is (as you know COM are stored in DLL usually)
so when ever you have to change a function you dont recompile all the project or EXE , you just recompile your Changed DLL and distribute it.




i dont know if it made it any clearer to you . I have the impression I just Made look worse. anyway Hope that helped.

[robinm]

COM or the Component Object Model is a specification.
The COM standard defines the following;

A common way for applications to access and perform operations on Objects.

A mechanism for keeping track of whether an object is in use and deleting it when it is no longer needed.

A mechanism for applications to exchange objects

A way to identify objects and to associate them with applications that understand how they are implemented.

(excerpt from DAN APPLEMAN - Developing COM/ACTIVEX Components)

[techman2553]

Thanks guys !!

I appriciate the input. I'll add this to the list of things that I need to research, practice, apply, and Master !!

[hellswraith]

I just read the VB COM book by Tomas Lewis. Pretty good. Very good place to start out.

[techman2553]

Thanks, I'll look for it!!