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WCF

LightInject.Wcf provides an integration that enables dependency injection in WCF applications.

Installing

PM> Install-Package LightInject.Wcf

This adds a reference to the LightInject.Wcf.dll in the target project.

Getting started

LightInject.Wcf aims to provide a zero config approach to developing WCF services in addition to support both constructor and property injection for WCF service implementations.

Note: If a Web site is precompiled for deployment, content provided by a VirtualPathProvider instance is not compiled, and no VirtualPathProviderinstances are used by the precompiled site.

The easiest way to create a new WCF application is to start with a new empty web application and then install the LightInject.Wcf package.

Our first service might look something like this:

[ServiceContract]
public interface IService
{
    [OperationContract]
    int GetValue(int value);
}

public class Service : IService
{
    public int GetValue(int value)
    {
        return value;
    }
}

The only thing we need to do is to create an ICompositionRoot implementation that registers our services and potentially its dependencies.

public class CompositionRoot : ICompositionRoot
{
    public void Compose(IServiceRegistry serviceRegistry)
    {
        serviceRegistry.Register<IService, Service>();
    }
}

That's it. No XML config, no .svc files, just press F5 to run the application.

Given that our service is defined in the SampleWcfApplication namespace, the service will be available at

http://localhost:xxxxx/SampleWcfApplication.IService.svc

Named Services

If we want to identify our service by something else than the full type name of the service interface, we need to register the service using a name.

public class CompositionRoot : ICompositionRoot
{
    public void Compose(IServiceRegistry serviceRegistry)
    {
        serviceRegistry.Register<IService, Service>("MyService");
    }
}

Now we need one additional class to bootstrap the container so that the service is registered with the correct name before the service is invoked.

[assembly: System.Web.PreApplicationStartMethod(typeof(SampleWcfApplication.Startup), "Initialize")]
namespace SampleWcfApplication
{
    using LightInject;
    using LightInject.Wcf;

    public class Startup
    {
        public static void Initialize()
        {
            var container = new ServiceContainer();
            container.RegisterFrom<CompositionRoot>();
            LightInjectServiceHostFactory.Container = container;
        }
    }
}

Behaviors

While it still is possible to configure endpoint and service behaviors using XML, LightInject.Wcf allows for IEndpointBehavior and IServiceBehavior implementations to be registered with the container so that they can be applied to the service.

public class SampleServiceBehavior : IServiceBehavior
{
    public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {            
    }

    public void AddBindingParameters(
        ServiceDescription serviceDescription,
        ServiceHostBase serviceHostBase,
        Collection<ServiceEndpoint> endpoints,
        BindingParameterCollection bindingParameters)
    {            
    }

    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {           
    }
}

public class SampleEndpointBehavior : IEndpointBehavior
{
    public void Validate(ServiceEndpoint endpoint)
    {            
    }

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

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
    }

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

In order to configure these endpoints we can simply register them with the container.

public class CompositionRoot : ICompositionRoot
{
    public void Compose(IServiceRegistry serviceRegistry)
    {
        serviceRegistry.Register<IService, Service>();
        serviceRegistry.Register<IServiceBehavior, SampleServiceBehavior>();
        serviceRegistry.Register<IEndpointBehavior, SampleEndpointBehavior>();
    }
}