Problems with about box in WPF application

I have tried adding an about box in blend using开发者_高级运维 the method described here:

About Window or About Box in WPF 3.5 (VS2008)

However, I end up getting an error saying that the namespace System.Windows.Forms doesn't exist.

Does blend not support this namespace? if so, is there another method for adding an about box?

Just create a normal WPF Window and make it look like an about box (add text blocks for product name, version, copyright ...)

There is nothing special about the WinForms about box, it's just a normal form preloaded with common about box controls, there is no reason to use it from WPF.