VB 6.0 to VB.NET Migration - Not supported features and Guidelines

Not Supported Features

Some features that were important to VB6 (and previous versions of VB) are not supported in VB .NET. If your legacy application relies heavily on these features, it may not be a good candidate for conversion. Important unsupported features include the following:

1.       OLE Container Control

2.       Dynamic Data Exchange (DDE)

3.       DAO or RDO Data Binding

4.       VB5 versions of the Windows Common controls and Data-bound Grid control

5.       DHTML applications

6.       ActiveX documents

7.       Property Pages

8.       User controls

9.       Web classes

As you can see, many of these unsupported features involve working with OLE (Object Linking and Embedding) and ActiveX or older controls. Part of the point of the .NET Framework is to phase out OLE, ActiveX, and, yes, even COM.

Guidelines

For successful migration please take the following points into consideration.

1.       Create a migration plan.

2.       Use the native object-oriented programming features of VB .NET in an object-oriented style.

3.       Don't convert VB6 portions of an application if it doesn't make sense to do so.

4.       Create a coding-standards document that covers topics such as variable-naming conventions and using constants rather than numerical values.

5.       Perform rigorous code reviews.

6.       Take the time to educate all programmers working on a project about .NET (well, maybe that's what this book is for!).

7.       Run programs at all times with Option Strict and Option Explicit turned on, so that variable declarations, strict typing, and explicit conversions are enforced. (You may want to get the upgraded application working first, and then go this extra step as a second stage.)

8.       Consider reworking the application architecture to use XML and web services to facilitate interoperability.