OLE

Introduction

In recent years I've been reading about OLE. I've tried to absorb the material as fast as I could although my progress seemed to be too slow due to the vast diversity of the subject. I've been working on type libraries and dispatch interfaces as well as generating interface codes for C++ programs (GenPro project can be mentioned as a result of this work), but there is still so much to learn and it takes a long time. Anyway I felt that it would be a great idea to develop small source codes and let the concept gradually sink in. Consequently I decided to devote a page on OLE and provide simple examples in it. These examples are written using pure C++ and without any framework such as OWL, OCF or MFC. Concepts and design methods are based on the book INSIDE OLE by Kraig Brockschmidt.

Examples

1. Simple Server, this example demonstrates how to develop a simple COM/OLE server. The project file consists of two targets, the one that builds the DLL server and the one that uses it. One of the features of this server is that it can register/unregister itself by implementing and exporting DllRegisterServer and DllUnregisterServer functions. Thus one can register the server by typing

   regsvr32 simpserv.dll

   on command line and unregister it by

   regsvr32 simpserv.dll /u.

   As I intend to add other features to this server, I have modified it from the previous version in order to prepare the scene for future extensions. If installed properly, this server exposes an interface that can be used to draw a rectangle of different colors in the client part of a given window. One can choose to modify the origin, dimension and color of this rectangle using the methods of exposed interface.

    

2. Dispatch Object, in this example, it is shown how to turn a simple object, such as the one in previous example, into an automation object. The steps are straight forward and are obvious from the code. It is necessary to add more information to the system registry and therefore extensive changes to DllRegisterServer and DllUnregisterServer functions are inevitable. In order to test the object, two applications are provided. One is written using OWL and also the code generated by GenPro and the other one is a simple VB script.

Last Updated: 12/26/2011