Return json object from WCF

See more:

ASP.NET

I have one class called "Device " and it declaration like as follow:

public class Device
    {
        public int DeviceID { set; get; }
        public string UserName { set; get; }

    }

I want to create one WCF where this service will return Device object in from of JSON.
can anyone tell me how to do it. And i also would like to know how i will consume this WCF...plz tell me its urgent