WPF Data validation in Powershell

Hi

I am using Powershell 3 to create a WPF GUI (using XAML code) and so far I have been able to create the form as I need and everything works fine. I was looking for data validation (specially in text box) and come across some articles about XAML styles and C# code for data validation. However, I am not sure how to convert those code to Powershell. I am particularly not sure how to use the C# class in Powershell. Can someone help please..

Here is the code sample that I was referring to:

http://msdn.microsoft.com/en-us/library/ms753962%28v=vs.100%29.aspx

tia,
uc

cheers..uc