title: How to add a custom HTTP header to every WCF call?
body: <p>I have a WCF service that is hosted in a Windows Service. Clients that using this service must pass an identifier every time they're calling service methods (because that identifier is important for what the called method should do). I thought it is a good idea to somehow put this identifier to the WCF header information.</p>
  
  <p>If it is a good idea, how can I add the identifier automatically to the header information. In other words, whenever the user calls the WCF method, the identifier must be automatically added to the header.</p>
  
  <p><strong>UPDATE:</strong>
  Clients that are using the WCF service are both Windows applications and Windows Mobile application (using Compact Framework).</p>