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COM I (Introduction)

First tutorial of the series COM, Introduction about the series. The series will contain topics like COM, DCOM, MTS, Pointers, Dynamic Memory Allocation, etc. Plus some basic Data Structures like Collections, Structures, Arrays, Enum, etc.

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COM – I
(INTRODUCTION)
[Visual Basic 6]
 
 
Friends, I am planning to post a complete series of
Tutorials under the title COM. COM, because basically we will be dealing with components.
The topics that we will cover in the series are:
 

 
Introduction
 
Using DLLs
   - Automation
 
Introduction
   to ADO
 
ADO
   (continued)
 
Arrays,
   Functions & Sub - Routines
 
Files,
   Structures, Enumerations & Collections
 
Dynamic
   Memory Allocation & Pointers in VB
 
Objects
   & Classes
 
Active
   – X DLL – Making our own COM
 
Interfaces
 
Collection
   Classes
 
Project
   to show the practical use of Components (covering collection classes,
   interfaces, etc.)
 
Active
   – X EXE
 
DCOM
 
MTS
 
Miscellaneous
   & Left Overs
 
Summary

 
If at any point of time you need help, you may contact me
at: [email protected].
 
The purpose of this series is to make new as well as
experienced programmers, get some in-depth idea of the above mentioned topics.
Many of these topics may not be called as parts of COM. But, I have included
them to make them clear so that we may use them in our components. Data
Structures (at least basic) must be clear! Don’t you think so?
 
Some topic might seem like C there like Pointers and Dynamic
Memory Allocation. These are very important concepts and need to be seen at
least.
 
After this point we are beginning with Object Oriented
Concepts and their implementation in VB. Here we will have in-depth
knowledge of Objects, Classes, COM, etc. Then, we will see some very
important concepts like Interfaces and their implementation in VB. 
 
After all this it is better to go for some Practical example
to show the usage of various concepts.
 
Then we will cover Active – X EXE, DCOM and MTS.
But, we will not be covering asynchronous callbacks here.
 
All this will greatly depend on your participation and
interest. So, I would feel good, if you give your precious suggestions and
comments. 

 
 

 
 
What is COM?
 
COM stands for – Component Object Model. It is basically a
concept which suggests that a larger piece of code must be broken down into
smaller components (specialized for some particular task). These components are
integrated and used as a whole. 
 
 
Why use COM?
 
Answer to this question is basically based on feeling…
See, Assume that you are given a task of making a
software for school.
Now, if you see as a whole a school is a very large
system. And, it is very difficult to implement the whole functionality of a
school.
So, if you get this project what will happen:
For some days you will continue that project, But soon it
will become unmanageable as you will start feeling bored. Somehow, you will
finish and the project will have many bugs.
 
It will be very difficult to remove the bugs as the code
is very unstructured. And, the efficiency of the overall system will be very
poor. The solution is, implement small-small functionalities on at a time
perfectly, and lastly integrate them. This is called COM.
 
Writing code for smaller things is very easy, and you
constantly feel that yes, something has been done!
 
<The exact example and need of COM will become more
clear when we go for Classes>

 
There was nothing much today, It
was just introduction. The actual thing will start from next one.
 

 
 
NOTE: Your feedback is
the fuel by which the series will be moving……
 
 
 
Bye,
Best of Luck,
 
Rahul
Vyas
([email protected])