System.Windows.Interactivity.WPF 2.0.20525

Microsoft Expression Blend 4 SDK includes new built-in behaviors, which are reusable pieces of packaged code that can be attached to any DependencyObject, and then fine-tuned by changing their properties. Behaviors allow you to add interactivity to your applications without having to write any code. The Behavior API consists of three core classes: Trigger, Action and Behavior.