Something we (Matt and I)have been working on for the past few days has been trying to be able to validate input forms in Silverlight. Seeing as how there wasn't a fairly straightforward framework...we decided to build our own! So, without further delay... Here it is, version 1: Silverlight.Validator
I noticed while working with Attached Properties and Dependency Properties that the code snippet is wrong. It keeps on trying using the UIPropertyMetadata. My guess is that this is an older version of the Register methods. So, here is a link (to my skydrive) that you can download and update your code snippets: cid-af5c4f2a863b6b78.skydri... Just download the two snippets and place them in your "%Program Files%\Microsoft Visual Studio ......