Open Visual Studio and create a new C# console project called Chapter7.WCFDiscovery. This will be the new service that we will discover.

Now add references to the System.ServiceModel and System.ServiceModel.Discovery assemblies and replace Program.cs with the following code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.ServiceModel.Discovery;
using System.ServiceModel.Description;

namespace Chapter7.WCFDiscovery
{
  public class Program
  {
    static void Main(string[] args)
    {
      ServiceHost host =
       new ServiceHost(typeof(ToUpperService),
               new Uri("http://localhost:8081/DiscoverMe"));
      host.AddServiceEndpoint(typeof(IToUpper),
                  new BasicHttpBinding(), "ToUpper");
      host.AddServiceEndpoint(typeof(IToUpper),
                  new WS2007HttpBinding(), "ToUpper2");
      host.Description.Behaviors.Add(
       new ServiceMetadataBehavior() { HttpGetEnabled = true }
      );

      ServiceDiscoveryBehavior discoveryBehavior =
       new ServiceDiscoveryBehavior();
      host.Description.Behaviors.Add(discoveryBehavior);

      host.AddServiceEndpoint(new UdpDiscoveryEndpoint());
      discoveryBehavior.AnnouncementEndpoints.Add(
       new UdpAnnouncementEndpoint()
      );

      host.Open();

      Console.WriteLine("Service running");
      Console.ReadKey();

    }

    public class ToUpperService : IToUpper
    {
      public string ToUpper(string Input)
      {
        return Input.ToUpper();
      }
    }
  }

[ServiceContract]
  public interface IToUpper
  {
    [OperationContract]
    string ToUpper(string Input);
  }
}

Now add another console project to the solution called Chapter7.WCFFindServices. Add references to the System.ServiceModel and System.ServiceModel.Discovery assemblies.

We now need to generate a proxy to enable us to call the service in the Chapter7.WCFDiscovery project. To create the proxy, we need to have Chapter7.WCFDiscovery running, so right-click the Chapter7.WCFDiscovery project and select Debug "Start new instance" (click Allow if you get a security warning).

You can check that the service is running correctly by opening a web browser and going to http://localhost:8081/DiscoverMe, where you should be presented with the service metadata page.

Open a Visual Studio command prompt and enter the following command to generate a proxy class for this service:

svcutil.exe http://localhost:8081/DiscoverMe?wsdl

Copy the generated proxy class (which will be at the Visual Studio command prompt location) to the Chapter7.WCFFindServices project.

In Chapter7.WCFFindServices, amend Program.cs to the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel.Discovery;
using System.ServiceModel;

namespace Chapter7.WCFFindServices
{
  class Program
  {
    static void Main(string[] args)
    {
      DiscoveryClient discoveryClient =
       new DiscoveryClient(new UdpDiscoveryEndpoint());
      Console.WriteLine(
       "Finding end points please wait this may take some time.."
      );

      FindResponse discoveryResponse =
       discoveryClient.Find(new FindCriteria(typeof(ToUpperClient)));

for (int Index = 0; Index < discoveryResponse.Endpoints.Count; Index++)
      {
        Console.WriteLine("Found end point at: " +
         discoveryResponse.Endpoints[Index].Address.ToString());
      }
      Console.WriteLine("Using end point: " +
       discoveryResponse.Endpoints[0].Address.ToString());

      EndpointAddress address = discoveryResponse.Endpoints[0].Address;

      ToUpperClient service =
       new ToUpperClient(new BasicHttpBinding(), address);
      Console.WriteLine(service.ToUpper("make me uppercase!"));
      Console.ReadKey();
    }
  }
}

OK, we're ready to go, so start up the Chapter7.WCFDiscovery project first (otherwise, you are not going to find anything) by right-clicking it, and select Debug "Start new instance." Once Chapter7.WCFDiscovery is running, start up the Chapter7.WCFFindServices project in the same manner. After a few minutes, you should find that the service is discovered and invoked as shown in Figure 7-2.

Figure 7.2. WCF discovery example