When storing business information in Windows SharePoint Services 3.0, you might experience scenarios in which important business data does not conform to the field types included in Windows SharePoint Services, or situations in which you need to further customize those general field types. Windows SharePoint Services offers the ability to create custom field types, based on the robust set of base field types it provides. These custom fields can include custom data validation, custom field rendering, and custom field property rendering and processing.
Microsoft Visual Studio 2005 Extensions for Windows SharePoint Services 3.0 gives new support for creating custom SharePoint field types. This Office Visual How To shows what you need to do to build a custom field type for Windows SharePoint Services 3.0 by using Microsoft Visual Studio 2005 with Extensions for Windows SharePoint Services 3.0. The field type created here provides you with the ability to select a logo image from a list box.