VALIDATION APPLICATION BLOCK (PRE-RELEASE) http://vab.codeplex.com This is a pre-release version. It is meant for developers to try out new features or bug fixes ahead of an official release. We strongly urge you to only use official builds for production. The latest official release is available at http://msdn.microsoft.com/entlib and via the NuGet official feed (http://nuget.org). Summary: The Validation Application Block provides useful features that enable developers to implement structured and easy-to-maintain validation scenarios in their applications. In addition, the Validation Application Block includes adapters that allow you to use the application block with ASP.NET, WCF, WPF, and Windows Forms applications. Microsoft patterns & practices http://microsoft.com/practices