title: WCF service calls to clients
body: <p>I am trying to create WCF service to handle client requests and modify a database. Beside my user clients i also have other interfaces, which can call my WCF service and modify the database.</p>
  
  <p>My problem is, I wish to notify my clients about the database change occured because of my other interface.</p>
  
  <p>So basicly: Clients are running, WCF service hosted by WAS/IIS, database changes and service should notify all of my connected clients about the change.</p>
  
  <p>My user clients are simple WinForms applications and the service is referenced to them.</p>
  
  <p>I would like to avoid initiating calls from the clients and waiting for the response, i'd rather like the service to make the call in the clients direction.</p>
  
  <p>My question is that is there a way to implement this, or i should use something like a listener?</p>