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Set Default Interceptor Unity Extension

With Unity, it is quite easy to implement an extension that automatically sets the appropriate interceptor for each registered type.

Here is how I did it:

public class DefaultInterceptorInterceptionExtension : Interception


     private static readonly IInterceptor [] interceptors = null;    static DefaultInterceptorInterceptionExtension()


        interceptors = (from interceptorType in

        (from type in typeof(IInterceptor).Assembly.GetExportedTypes()

        where typeof(IInterceptor).IsAssignableFrom(type) &&

        type.IsAbstract == false &&

        type.IsInterface == false

        select type)        select Activator.CreateInstance(interceptorType) as IInterceptor).ToArray();


    protected override void Initialize()



        IConfigurationSource configSource = ConfigurationSourceFactory.Create();

        PolicyInjectionSettings section = configSource.GetSection(PolicyInjectionSettings.SectionName) as PolicyInjectionSettings;

        if (section != null)


this.Container, configSource);


        this.Context.Registering += new EventHandler<RegisterEventArgs>


            delegate(Object sender, RegisterEventArgs e)


                this.setInterceptorFor(e.TypeFrom, e.TypeTo, e.Name);



        this.Context.RegisteringInstance += new EventHandler<RegisterInstanceEventArgs>


            delegate(Object sender, RegisterInstanceEventArgs e)


                this.setInterceptorFor(e.RegisteredType, e.Instance.GetType(), e.Name);




    private void setInterceptorFor(Type typeToIntercept, Type typeOfInstance, String name)


        foreach (IInterceptor interceptor in interceptors)


            if ((interceptor.CanIntercept(typeToIntercept) == true) && (interceptor.GetInterceptableMethods(typeToIntercept, typeOfInstance).Count() != 0))


                if (interceptor is IInstanceInterceptor)


                    this.Container.Configure<Interception>().SetDefaultInterceptorFor(typeToIntercept, interceptor as IInstanceInterceptor);


                else if (interceptor is ITypeInterceptor)


                    this.Container.Configure<Interception>().SetDefaultInterceptorFor(typeToIntercept, interceptor as ITypeInterceptor);







And you register with like this:



        <typeAlias alias="singleton" type="Microsoft.Practices.Unity.ContainerControlledLifetimeManager, Microsoft.Practices.Unity, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />

        <typeAlias alias="transient" type="Microsoft.Practices.Unity.TransientLifetimeManager, Microsoft.Practices.Unity, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />

        <typeAlias alias="external" type="Microsoft.Practices.Unity.ExternallyControlledLifetimeManager, Microsoft.Practices.Unity, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />

        <typeAlias alias="thread" type="Microsoft.Practices.Unity.PerThreadLifetimeManager, Microsoft.Practices.Unity, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>





                <add type="DefaultInterceptorInterceptionExtension, SomeAssembly" />





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sonali said:

I am getting some exception with this code..I would like to send my code could you please give me email id where I can upload my sample code...

Otherwise if you please send me the sample using this code.

# June 4, 2010 6:16 AM

Ricardo Peres said:


That is the code I use. What exception are you getting exactly, and where?

# June 4, 2010 8:01 AM

GPS Blocker said:

Very good article!just what I am looking for!

# September 21, 2010 10:29 AM