As the title suggests, this book has two separate - though intertwined - goals: a description of the general concepts of object-orientation, and how to do object-oriented programming in Visual Basic. Readers are assumed to have no more than a familiarity with Visual Basic and some rudimentary knowledge of programming. Working on this premise, Steve Roman introduces the abstract concepts of object orientation, such as class, abstraction, and encapsulation, and then shows how each is implemented in a meaningful and useful application. He uses a hands-on style throughout: plenty of code is given and discussed, including error-handling. As a result, Visual Basic programmers and students will find this an invaluable introduction to the topic.

1 The Basics of Object-Oriented Programming.- Data Types.- Encapsulation.- Abstract Data Types.- Classes.- Defining a Class in Visual Basic.- Defining a Property in Visual Basic.- Defining a Method in Visual Basic.- Exposing Properties Through the Property Let/ Set/ Get Procedures.- Objects.- Explicit Object Creation.- Instance Variables and Member Variables.- The As Object Syntax.- Implicit Object Creation.- Referencing Public Variables and Procedures.- The Object/Message Model.- The Me Keyword.- Object Properties and Object Hierarchies.- Creating and Destroying Objects.- Creating Objects.- Destroying Objects.- Reference Counts.- Circular References.- The Notorious End Statement.- How to Control a Circular Reference-A Linked List Example.- Form Modules.- Properties and Methods in a Form Module.- Collection Classes.- Constructing a Collection Class.- Polymorphism and Overloading.- Overloading.- Polymorphism.- Inheritance.- 2 Handling Object Errors.- Error Detection and Error Handling.- Types of Errors.- The Error Object.- Dealing with Run-Time Errors.- Where to Handle a Run-Time Error.- Dealing with Logical Errors.- Detecting Logical Errors.- Where to Handle a Logical Error.- Handling the Error in the Calling Procedure.- Errors Occurring in Events.- An Error-Handling Example.- 3 Turing Machines - A Simple Object-Oriented Application.- What Is an Algorithm?.- What Is a Turing Machine?.- Informal Definition of a Turing Machine.- Describing a Turing Machine.- Coding a Turing Machine.- Error Handling.- The Symbol Class.- The Symbols Collection Class.- The State Class.- The States Collection Class.- The Transition Class.- The Transitions Collection Class.- The Machine Class.- The User Interface.- The Standard Module.- A Final Comment.- 4 OLE Automation Objects.- What IsOLE Automation?.- Public Really Means Public.- The Plan for This Chapter.- Communication Between OLE Automation Clients and Servers.- The Communication Problem.- Supplying Information to the Client.- What Is an Interface?.- The Vtable Interface.- Type Libraries.- OLE Interfaces.- The IUnknown Interface.- The IDispatch Interface.- Binding.- Putting It All Together.- In-Process and Out-of Process Servers.- Creating a Simple OLE Automation Server.- Creating a Simple Server.- A Small Client and the Three Forms of Binding.- Referencing the Server's Type Library.- Registering and Unregistering a Server.- How Servers Are Started and Ended.- Reference Counts for Servers.- Servers with a Visual Interface.- Servers with Dialog Boxes.- OLE Servers That Also Function as Stand-Alone Applications.- Handling Errors.- Be Nice.- Errors from Your Server's Servers.- Externally Creatable and Dependent Objects - The Object Hierarchy.- In-Process Issues.- Version Compatibility.- How Compatibility Can Be Affected.- How Visual Basic Handles Compatibility.- The Reference Server and Interim Builds.