Microsoft's Visual Basic is about to sprout some powerful legs this year in the form of Visual Basic.NET. Companies planning to adopt Visual Basic.NET will be able to leverage application capabilities, such as inheritance, that were previously confined to other languages, C++ for example. But the move to Visual Basic.NET is not merely a programming language upgrade; developers who have expertise in Visual Basic 6 will need to learn major new programming concepts.
Business leaders face the tough choice of whether to migrate or rewrite existing Visual Basic 6 applications using Visual Basic.NET or to adopt a different business application development platform altogether, such as Java. Either choice will require a sizeable investment in both developer coding and training.
If your company has invested in the Windows platform as its primary application-serving vehicle and doesn't see a strategic need to deviate from that, then investing in Visual Basic.NET is a good choice. On the other hand, if your company's application needs will potentially outgrow Microsoft technologies, then this may be a good time to perform a cost/benefit analysis that includes other platform choices.
Decisions to rewrite business applications using Visual Basic.NET will require a significant amount of work. IT directors will want to redesign applications to leverage the powerful capabilities that Microsoft has introduced with Visual Basic.NET. This means that your company will need to invest in another round of design, coding, testing, and developer training that should be viewed as a long-term effort toward a successful implementation.
Developer tips
IT managers and development teams should begin a series of projects that examine their existing Visual Basic 6 code with an eye toward forthcoming changes.
1. Get business logic out of forms. Applications that contain business logic at the form layer will not easily migrate to Visual Basic.NET. Move the logic into components and classes for a smoother transition.
2. Get SOAPed up. Take a look at Microsoft's SOAP (simple object access protocol) implementation, as it will enable Visual Basic.NET objects to interact via the Web.
3. Don't use currency and variant types. Visual Basic.NET will not support these types. Use decimal types instead of currency. Visual Basic.NET will replace variants with support for object types.
4. Check your arrays. Visual Basic.NET supports only zero-based arrays. Change existing arrays to be zero-based to make the transition easier.
5. Don't use default properties. Visual Basic 6 saves you time by letting you access the default properties for an object. In contrast, Visual Basic.NET requires that you explicitly define the property, function, or method you want to use. Existing objects should be inspected and explicitly defined.
6. Check for obsolete keywords. Visual Basic has, until now, carried backward support for QuickBasic-compatible keywords. With Visual Basic.NET, this support goes away, so locate any of the keywords that will become obsolete and remove them from your code.
7. Watch out for variable declarations. In Visual Basic 6, you can declare a variable anywhere in a routine, and it will be available. Visual Basic.NET introduces the concept of block-scope, which changes variable declaration. The easiest way to grapple with this change is to declare all variables at the top of a routine.
8. Change your form-loading process. In Visual Basic 6, a load is formed by merely referring to it. With Visual Basic.NET, you'll need to declare a form variable, instantiate it, and then show it.
9. Expect conditionals to be processed differently. Both parts of a conditional are evaluated in Visual Basic 6, but because Visual Basic.NET shares a common run time with other languages, it handles Boolean logic differently. For example, if the first part of a conditional is false in an AND operation, the second part of the conditional will not be evaluated.
10. Simulate enhanced use of inheritance and object concepts. Get a jump on learning the object-oriented concepts supported in Visual Basic.NET. Look for materials that discuss how to simulate the way Visual Basic.NET will treat concepts, such as inheritance, using Visual Basic 6.
Next steps
These are but a few things Visual Basic developers need to consider as they prepare for Visual Basic.NET. Because no additional effort will be required to adopt a new application development strategy, now is a good time to re-evaluate your company's commitment to Microsoft's Visual Basic programming language.
Contributing Editor Maggie Biggs has more than 15 years of strategic and tactical business and IT experience.
Ensuring the future of Visual Basic applications1. Decide whether to migrate or rewrite applications for Visual Basic.NET or to move to another platform.
2. Inspect your code and make changes with your future platform in mind.
3. Invest in developer training to get up-to-speed on new concepts.
4. Redesign, migrate or rewrite, test, and implement your new applications.