Question

I am trying to learn WCF with this example
http://www.codeproject.com/Articles/39143/C-WCF-Client-Server-without-HTTP-with-Callbacks-Ma

Also trying to extend the functionality on the server by adding mutual exclusion with multiple clients.
I am basically trying to have a global array of numbers and a function(which has been exposed with an Operationcontract) that can access this array.But only one client is allowed to access the array at a time.

Can someone point me in the right direction by adding a simple function with a mutual exclusion lock?

Answer 1

Depending on what exactly you want to do, how about putting a lock around the function accessing your array (maybe event put your array into a singleton).

Then you could have

class SingletonClassForYourArray {
   object aLock = new object();
   int yourArray;
   private SingletonClassForYourArray instance;

   public SingletonClassForYourArray GetInstance()
   {
   // normal singleton init of instance on demand
   }

   int [] YourArray 
   {
       get 
       {
           lock(aLock)
           {
               return yourArray;
           }          
       }
   }
}

This would be the easiest way to have only one client access the array. All clients without the lock will have to wait in turn (fairness not guaranteed). Be careful as this may result in timeouts if clients have to wait to long.