title: Understanding dependency property system
body: <p>Could someone help me to figure out with dependency property system in WPF?! I just wanted to do something like this:</p>
  
  <p>Assume, class A have a property (DP) called "A_property". Another class B just represent some business logic and I wanted this class would be able to monitor "A_property". I mean that class B should subscribe class A's property. If someone so kind, please, provide me a sample how to do that using dependency property system?</p>
  
  <p>P.S. It's clear to me how to solve the above problem using RoutedEvent, but it seems to me that DP system should simplify the solution.</p>
  
  <p>Thanks in advance!</p>