3 Approach to achieve Async call in WCF

Approach One: using proxy client)

http://msdn.microsoft.com/en-us/library/ms730059.aspx

event-driven asynchronous calling model

Service Side

 [ServiceContract]    public interface IService    {        [OperationContract]        double Add(double a, double b);    }

    public class Service : IService    {        public double Add(double a, double b)        {            return a + b;        }    }

Generate Asyn Proxy

C:\windows\system32>svcutil http://localhost:8000/mex /a /tcv:Version35

Client Side

   static void Main(string[] args)        {            Console.WriteLine("Press <ENTER> to terminate client once the output is displayed.");            Console.WriteLine();            // Create a client            ServiceClient client = new ServiceClient();            // AddAsync            double value1 = 100.00D;            double value2 = 15.99D;            client.AddCompleted += new EventHandler<AddCompletedEventArgs>(AddCallback);            client.AddAsync(value1, value2);            Console.WriteLine("Add({0},{1})", value1, value2);            Console.ReadLine();        }        // Asynchronous callbacks for displaying results.        static void AddCallback(object sender, AddCompletedEventArgs e)        {            Console.WriteLine("Add Result: {0}", e.Result);        }

Approach Two: Using Channel Factory

http://msdn.microsoft.com/en-us/library/bb885132.aspx

Service Side

 [ServiceContract]    public interface IService    {        [OperationContract]        double Add(double a, double b);    }

    public class Service : IService    {        public double Add(double a, double b)        {            return a + b;        }    }

Generate Asyn Proxy

C:\windows\system32>svcutil http://localhost:8000/mex /a

Client Side

     static void Main(string[] args)        {            ChannelFactory<IServiceChannel> factory = new ChannelFactory<IServiceChannel>("BasicHttpBinding_IService");            IServiceChannel channelClient = factory.CreateChannel();            // BeginAdd            double value1 = 100.00D;            double value2 = 15.99D;            IAsyncResult arAdd = channelClient.BeginAdd(value1, value2, AddCallback, channelClient);            Console.WriteLine("Add({0},{1})", value1, value2);            Console.ReadLine();        }        static void AddCallback(IAsyncResult ar)        {            double result = ((IServiceChannel)ar.AsyncState).EndAdd(ar);            Console.WriteLine("Add Result: {0}", result);        }    }

Approach Three: Add Service Reference

Client Code:

 static void Main(string[] args)        {            ChannelFactory<IService> factory = new ChannelFactory<IService>("BasicHttpBinding_IService");            IService channelClient = factory.CreateChannel();            // BeginAdd            double value1 = 100.00D;            double value2 = 15.99D;            IAsyncResult arAdd = channelClient.BeginAdd(value1, value2, AddCallback, channelClient);            Console.WriteLine("Add({0},{1})", value1, value2);            Console.ReadLine();        }        static void AddCallback(IAsyncResult ar)        {            double result = ((IService)ar.AsyncState).EndAdd(ar);            Console.WriteLine("Add Result: {0}", result);        }

OR

 static void Main(string[] args)        {            Console.WriteLine("Press <ENTER> to terminate client once the output is displayed.");            Console.WriteLine();            // Create a client            ServiceClient client = new ServiceClient();            // AddAsync            double value1 = 100.00D;            double value2 = 15.99D;            client.AddCompleted += new EventHandler<AddCompletedEventArgs>(AddCallback);            client.AddAsync(value1, value2);            Console.WriteLine("Add({0},{1})", value1, value2);            Console.ReadLine();        }        // Asynchronous callbacks for displaying results.        static void AddCallback(object sender, AddCompletedEventArgs e)        {            Console.WriteLine("Add Result: {0}", e.Result);        }