The following months I will be spending most of my study time on the Windows Communication Foundation (WCF). I participated on several projects using WCF in the past few years, mostly consuming services. Let’s crank this knowledge up a notch. I need a basic WCF Service Library for testing purposes.

Here’s what I came up with. I created a solution with both a WCF Service Library and a test project for my services. The ‘Hello World’ of communications for me is the Echo Service; somewhat reassembling the TCP Echo Protocol. A simple service given a EchoMessage returning an echo of that message (3x) to the client.

First I need a datacontract to call and return the EchoService with – EchoMessage.

using System;
using System.Runtime.Serialization;
 
namespace WcfServiceLibrary.Echo
{
    [DataContract]
    public class EchoMessage
    {
        public EchoMessage()
        {
            Created = DateTime.Now;
        }
 
        [DataMember]
        public string Text { get; set; }
 
        [DataMember]
        public DateTime Created { get; set; }
 
        [DataMember]
        public DateTime? Invoked { get; set; }
    }
}

Then I created the IEchoService interface, exposing the actual ServiceContract and operations of the service.

using System.ServiceModel;
 
namespace WcfServiceLibrary.Echo
{
    [ServiceContract]
    public interface IEchoService
    {
        [OperationContract]
        EchoMessage Echo(EchoMessage message);
    }
}

Finally I added the EchoService class implemenation of the IEchoService interface, with some trivial business logic for the Echo operation. I did not add any ServiceBehavior or OperationBehavior to further configure the service, effectively using the default values.

using System;
using System.Linq;
 
namespace WcfServiceLibrary.Echo
{
    public class EchoService : IEchoService
    {
        #region IEchoService Members
 
        public EchoMessage Echo(EchoMessage message)
        {
            message.Invoked = DateTime.Now;
            message.Text = String.Concat(
                Enumerable.Repeat(message.Text, 3));
 
            return message;
        }
 
        #endregion
    }
}

After a successful build and run the WCF Service Host and the WCF test client starts. We can now invoke the Echo operation of the EchoService to send back and forth EchoMessages.