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VB Coding Standards - VB.Net 2
Continuing on from last week's VB Coding Standards Update(1), in preparation for the next version of Visual Basic, due for release H2, 2001, some fundaments VB coding approaches will have to change to accommodate VB.NET. Here are more simple changes which are required for VB.NET, and can be integrated into current versions of VB. One thing is for sure, most of your current programs will not run in VB.NET without some manual intervention, so employing these coding procedures would make the migration easier.

Variable Declarations:
The rules defining variable declarations are to change, by including new syntax and not supporting some of the current syntax. Multiple datatype declarations can be coded on one line as follows:

   Dim strName as String, intAge as Integer, decSalary as Decimal

While default datatype declarations such as:

   Dim Wage, ShoeSize as Integer

where Wage would have become Variant in VB6, will become Integer in VB.NET. Unless screen space is a real issue, play safe and declare variables on separate lines.

Currency and Variant Datatype to go:
VB.NET will no longer support currency and variant datatypes. Currency will be replaced with the new 64 bit Long datatype (or Decimal datatype). NOTE: Datatypes cannot be declared as Decimal, but can be converted using cDec to make them a Decimal subtype.
Variant datatypes are to be replaced with Object datatypes for most purposes, but best avoided if possible, especially where a more appropriate datatype can be employed.

API Call Arguments:
As the Long datatype in VB.NET will be 64 bit, and Win32 API calls accept 32 bit Long arguments, most API calls will fail unless these arguments are re-declared as the new Integer datatype. To clarify....
VB6's Integer will become 'Short' in VB.NET; VB6's Long will become 'Integer' in VB.NET; and VB.NET new 64 bit 'Long' doesn't have an equivalent in VB6.

Split out your Business and Presentation Logic
Look for opportunities to encapsulate your logic in classes, as classes are the easiest modules to migrate to VB.NET. Where your applications are based around rich clients containing a mixture of business and presentation logic, these will prove the most difficult to accommodate. Ideally, the more logic you have in components and classes, and the thinner client, the better. This is due to the introduction of WebForms and WinForms, and a greater distinction between the UI and code components/classes.

 

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