Custom Field Types and WSS 4.0′s XSLT-based Field Type

I just posted an article related to the List View Web Part and WSS 4.0’s XSLT-based List View Web Part – I had known about this change for quite some time but this other change was new to me. It appears that there will now be a new XSLT-based field type. The following article discusses the upgrade issues for custom field types: The CustomFieldType rule in Pre-Upgrade Checker in Windows SharePoint Services 3.0 Service Pack 2 can warn that customized field types will not be upgraded. Here’s a snippet of the relevant information:

A field type that uses custom Collaborative Application Markup Language (CAML) in its RenderPattern element will not be upgraded as an XSLT-based field type. Fields based on this custom field type will be rendered without any custom formatting in the next release of Windows SharePoint Services.

As in my previous post about the LVWP there are two takeaways here – the first is that there will be a new XSLT-based field type in the next version and the second, and more important point, is that if you are creating custom field types and using custom CAML in the RenderPattern element you will have to reset that element to use XSLT after the upgrade completes. Also, you might notice a bit of a trend with these two articles – it would appear that Microsoft is moving certain aspects of the product away from CAML – all I can say to that is, YIPPEE!!!