The VB5 Programmer's Guide To VB6When a new version of Visual Basic is released, the first thing every VB programmer wants to know is, "What's new, and how can I use it to my benefit?" This entire book is geared towards answering that important question, and this chapter will provide you with brief descriptions of some of the new features of VB6. However, before we get into the details of how Visual Basic 6 differs from VB5, let's go back and quickly recap the major changes that have been introduced with prior releases of the product. The original version of Visual Basic was rather limited, and was by no stretch of the imagination a tool for serious development. However, it was a landmark product in that it brought a graphical design environment to the world of Windows development. It was neat, but it was also seen by the majority of programmers as a "toy" language. The subsequent version of the product, VB2, didn't really do much to enhance Visual Basic's position in the development world because it still lacked native database support. However, Access 1.0 was released shortly after VB2, and the beginnings of a marriage between the two started to take hold. It wasn't until VB3 was released that Visual Basic really started to gain support from the development community. Among other innovations, the new version added the Jet database engine, giving VB the built-in database support that it so desperately needed. VB3 also added support for VBX modules, the 16-bit predecessors to the OCX components used in later versions of the product. Third-party support for Visual Basic really started to increase with the release of VB3. It was also about this time that VB was starting to gain recognition as a viable development environment. It still had a long way to go, but VB was finally starting to take shape as a powerful and flexible programming language. VB4 was something of a "stepping stone" designed primarily for easing the transition between 16-bit and 32-bit development. In fact, VB4 actually consisted of two separate development environments: one for 16-bit applications and one for 32-bit applications. Because of the support for 32-bit development, it was in VB4 that we first saw the 32-bit OCX controls that are now so commonplace. VB4 added some other important new features, such as the ability to create OLE custom controls and DLLs. Because Access 2.0 was released after VB3, VB4 also addressed compatibility issues between the Jet engine and the newer version of Access. Although VB4 brought quite a few changes to the Visual Basic environment, the next version really gave it a boost. VB5 added a slew of new project types, including ActiveX controls, ActiveX DLLs, and ActiveX documents. VB's compiler received an overhaul as well, so that VB could support native code compilation in addition to pseudocode (P-Code) compilation. This brings us to the current version of Visual Basic, VB6, and that same question, "What's new?". The paradoxical answer: a little and a lot. On one hand, there are few major changes that have been made, and VB6 is really not very different from VB5. On the other hand, VB6 has a long list of minor changes, ranging from new language features to a re-vamping of the Setup Wizard (now called the Package and Deployment Wizard). Like VB4, VB6 seems to be a stepping stone rather than a major overhaul of the development environment. In VB4, the move was towards 32-bit application development. This time, Microsoft is easing Visual Basic programmers into a new database accessing method (ADO) that is destined to eventually take the place of other accessing methods such as DAO and ODBC. Therefore, it should be no surprise that many of the new features found in VB6 are in the area of data access. ADO, or ActiveX Data Objects, has been implemented in VB6 as an ActiveX control (the ADO Data control). |
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