TABLE OF CONTENTS Object-oriented programming (OOP) is a buzzword in computer programming circles. In this chapter we will discuss what it means and how you use it in relation to AutoCAD customization. We will devote the beginning sections of the chapter to objects and object-oriented programming practices. Toward the end of the chapter we will pay specific attention to how to use VBA to accomplish the interface.
Object-oriented programming provides a tool by which applications developers can exploit complete software mechanisms already written and fully tested by other programmers. In VBA, we use tools provided by the programmers at Autodesk who created AutoCAD. The primary advantage of this module-based programming is that once a module is written and fully tested, we can use it with the knowledge that the component is fully functional in its own way. The key to successfully developing such modules for use by others is to identify the confines of the activities it performs. That is what the module does, can do, wants to do, should do, and so forth.
An applications programmer can use these software mechanisms, called objects, to accomplish task inside a software environment such as AutoCAD. AutoCAD provides an extensive interface system that allows programmers to directly access the drawing database and drawing editor environment. A computer application such as AutoCAD can offer various depths of access into itself. The depths of access are often referenced as the amount of exposure that a program provides to an environment. The ActiveX/VBA interface grants very...
