XSL operations and MSXML library migration

Subject

MSXML library migration

Applies to

Visual Basic Upgrade Companion Enterprise Edition, Visual Basic Upgrade Companion Developer Edition

Inquiry Description

VBUC migrates MSXML classes to .Net native xml classes. How does it upgrade XSL related operations? Can the VBUC also re-format XSL files to avoid problems?

Troubleshooting/solution

The VBUC does not format or change XSL files associated with code.

However, from past experiences we can confirm that it is sometimes necessary to perform changes in XSL documents when using .NET’s System.Xml namespace in a migration. Changes were only necessary in a fraction of the XSL files and in no instance did all XSL files require changes.

In one project, which relied heavily on XSL documents, only 10% of the more than 180 different XSL files required changes. Most of these changes were minor or involved changing an XPath query. Most changes related to problems encountered by .NET XML parser when applying a transformation and could be checked with tools such as XMLSpy or OxygenXML configured to use .NET’s parser.

When comparing the output between .NET and VB6 most differences involved whitespace and other formatting concerns. One particular case to watch out for is the serialization of dates in .NET versus VB6.

Detecting most of these issues prior to migration proves difficult. This is because VB6 is quite fault tolerant and will keep processing an XSL even if errors or inconsistencies are detected. The .NET framework is not as forgiving and will throw an exception if an error or fault is detected. Therefore, verifying XSL files with an external tool can help detect possible problems.