Question

Let’s assume I have a windows forms application that should be remote-controlled or influenced from a remote location with .net.

As far as I’ve googled, hosting a WCF service inside that application would be the way to go. I’ve successfully added a WCF service to the application and can start it with

    ServiceHost host = new ServiceHost(typeof(Service1));   
    host.Open();

What would be a good way to get references to classes from the rest of the running application?
I guess there are only these 2 ways:

• Use of static properties to call other methods / set properties from within the service method.
• Assign references to the service class? (How do I assign values to the service hosted within the service host? )

What is considered a good practice or rather which way has worked for you in the past?

Update based on comment
I’m guess I’m looking for something like this:

    ServiceHost host = new ServiceHost(typeof(Service1));   
    host.Open();  
    (Service1)host.MyProperty = "asd";

I can’t seem to find how to cast the ServiceHost (or a property of it) to an instance of Service1. That would probably solve all my problems 😉

Answer 1

You can’t really do what you added based on the comment:

ServiceHost host = new ServiceHost(typeof(Service1));
host.Open();
(Service1)host.MyProperty = "asd";

Because at that point no instances of the class Service1 have been created yet. And they’ll only be created when a new request arrives for the service.

One alternative is to use a custom instance provider (shown in the code below), where you have a reference to the service instance before it’s used by the WCF runtime. You can read more about instance providers at http://blogs.msdn.com/b/carlosfigueira/archive/2011/05/31/wcf-extensibility-iinstanceprovider.aspx.

public class StackOverflow_10932251
{
    [ServiceContract]
    public interface ITest
    {
        [OperationContract]
        string Echo(string text);
    }
    public class Service : ITest
    {
        public string MyProperty { get; set; }
        public string Echo(string text)
        {
            Console.WriteLine("Inside Service.Echo, MyProperty = {0}", this.MyProperty);
            return text;
        }
    }
    static Binding GetBinding()
    {
        var result = new WSHttpBinding(SecurityMode.None);
        return result;
    }
    public class MyInstanceProvider : IEndpointBehavior, IInstanceProvider
    {
        string propertyValue;
        public MyInstanceProvider(string propertyValue)
        {
            this.propertyValue = propertyValue;
        }

        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
        {
        }

        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
        {
        }

        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
        {
            endpointDispatcher.DispatchRuntime.InstanceProvider = this;
        }

        public void Validate(ServiceEndpoint endpoint)
        {
        }

        public object GetInstance(InstanceContext instanceContext, Message message)
        {
            return new Service { MyProperty = this.propertyValue };
        }

        public object GetInstance(InstanceContext instanceContext)
        {
            return new Service { MyProperty = this.propertyValue };
        }

        public void ReleaseInstance(InstanceContext instanceContext, object instance)
        {
        }
    }
    public static void Test()
    {
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
        ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(ITest), GetBinding(), "");
        endpoint.Behaviors.Add(new MyInstanceProvider("asd"));
        host.Open();
        Console.WriteLine("Host opened");

        ChannelFactory<ITest> factory = new ChannelFactory<ITest>(GetBinding(), new EndpointAddress(baseAddress));
        ITest proxy = factory.CreateChannel();
        Console.WriteLine(proxy.Echo("Hello"));

        ((IClientChannel)proxy).Close();
        factory.Close();

        Console.Write("Press ENTER to close the host");
        Console.ReadLine();
        host.Close();
    }
}