Communication between WPF and hosted WCF Service

Question

I have a console app that starts a WCF service and a small WPF app. I'm trying to show a messagebox in the WPF app whenever a method on the WCF service is called for testing purposes. I have based my code on this answer but the synchronizationContext is null. How do i fix this? Or are there other/better ways to make this happen?

Answer 1

Use SignalR . Lots of info here and here . This article also looks very good.

As for actual code, create a WCF service and use NuGet to add a reference to SignalR, then add a hub class:

public class ServiceMonitorHub : Hub
{
}

You'll also need to add an Owin startup class to start the SignalR hub:

[assembly: OwinStartup(typeof(YourNamespace.SignalRStartup))]
namespace YourNamespace
{
    public class SignalRStartup
    {
        public void Configuration(IAppBuilder app)
        {
            app.MapSignalR();
        }
    }
}

Your service handlers can then get a reference to this hub and send messages to all the clients that are connected to it:

public class Service1 : IService1
{
    public string GetData(int value)
    {
        // send msg to clients
        var hub = GlobalHost.ConnectionManager.GetHubContext<ServiceMonitorHub>();
        hub.Clients.All.BroadcastMessage();

        return string.Format("You entered: {0}", value);
    }

Your WPF client then connects to this SignalR server and hooks in handlers to receive the messages send by the service handlers, this example contains a button handler that calls the service, as well as a connection to the SignalR hub to receive the messages that bounce back:

public partial class MainWindow : Window
{
    private HubConnection Connection;
    private IHubProxy HubProxy;

    public MainWindow()
    {
        InitializeComponent();
        Task.Run(ConnectAsync);
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        using (var service = new ServiceReference1.Service1Client())
            service.GetData(1);
    }

    public async Task ConnectAsync()
    {
        try
        {
            this.Connection = new HubConnection("http://localhost:59082/");
            this.HubProxy = this.Connection.CreateHubProxy("ServiceMonitorHub");
            HubProxy.On("BroadcastMessage", () => MessageBox.Show("Received message!"));
            await this.Connection.Start();
        }
        catch (Exception ex)
        {
        }
    }
}

}

Note that clients need the NuGet SignalR.Clients package (as opposed to just SignalR).

There are other ways for services to call the hub clients, this link shows a few others.

Answer 2

Maybe you could try ClientMessageInspector, the AfterReceiveReply of it will be called every time the client receives the message.

 public class MyClientMessageInspector : IClientMessageInspector
{
          Your message box
    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
       show message in your message box
    }
    public MyClientMessageInspector ( ){

                       }

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        return null;
    }
}

To register the Inspector , you need to use an endpointBehavior

  public class MyEndpointBehavior : IEndpointBehavior
{
    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {

    }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.ClientMessageInspectors.Add( new MyClientMessageInspector();
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {

    }

    public void Validate(ServiceEndpoint endpoint)
    {

    }
}

And then add the behavior to your client.

 using (ChannelFactory<IService> ChannelFactory = new ChannelFactory<IService>("myservice"))
        {
            ChannelFactory.Endpoint.EndpointBehaviors.Add(new MyEndpointBehavior());
            IService service = ChannelFactory.CreateChannel();
          // call method


        }