Pass string parameter from windows form application to windows service through wcf

The easiest way is using a self hosted WCF service. If the Service and client are on the same machine you can use an in memory named pipe binding.

http://msdn.microsoft.com/en-us/library/system.servicemodel.netnamedpipebinding.aspx

http://omegacoder.com/?p=101

or you could use a tcp binding if the client resides on a different machine http://msdn.microsoft.com/en-us/library/ms733769.aspx