Lazy Initialization in custom IDependencyResolver with Windsor Castle

Question

I am using Windsor Castle. I have a Business class and an Interceptor configured as following:

windsorContainer.Register(Component.For<IMyBusinessInterface>()
    .ImplementedBy<MyBusinessClass>()
    .Interceptors<MyInterceptorAttribute>()
    .LifestyleTransient());

IMyBusinessInterface and MyBusinessClass are inside the project Business. MyInterceptorAttribute is inside the project Interceptors. Business project has a reference to Interceptors project.

MyInterceptorAttribute is used as data annotation on a method of the MyBusinessClass

[MyInterceptorAttribute]
public class MyBusinessClass 
{
    public IUnitOfWork uow { get; set; }
    public MyBusinessClass(IUnitOfWork uow)
    {
        uow = uow;
    }

    [MyInterceptorAttribute]
    public MyReturnValue MyBusinessMethod(MyArguments arguments)
    {
        //...
    }
}

I need to pass (or retrieve) inside the MyInterceptorAttribute class the same instance of the unit of work that has been instanciated inside the container of Windsor Castle.

In this moment I pass two different instances.

I cannot retrieve the instance of unit of work inside the MyInterceptorAttribute because to get the invocation.InvocationTarget I would create a circular reference.

public class MyInterceptorAttribute : IInterceptor
{
    public void Intercept(IInvocation invocation)
    {
        IMyBusinessInterface obj = invocation.InvocationTarget as MyBusinessClass; //I cannot do this because of circular reference

        //obj.uow = ..

    }
}

So I was thinking to add a public property of unit of work inside the MyInterceptorAttribute and get same instance of unit of work of the business class via dependency injection... something like this:

public class MyInterceptorAttribute : IInterceptor
{
    public IUnitOfWork uow { get; set; }

    public void Intercept(IInvocation invocation)
    {
        //uow...            
    }
}

But in this moment I get two different instances. Is it possible to get the same instance modifying for example the configuration of windsor caste... I suppose using DependsOn or DynamicParameters or something similar?

Thank you

Phil Degenhardt Phil Degenhardt · Accepted Answer · 2017-04-18T00:50:47

Instead of implementing your interceptor as an attribute, which is instantiated by the .Net runtime and therefore not available for dependency injection by Windsor, try using the standard [Interceptor(typeof(MyInterceptor))] attribute.

You can then register MyInterceptorin Windsor with whatever lifestyle you wish and dependency injection for the Unit Of Work, or any other dependency, will work as expected.

Lazy Initialization in custom IDependencyResolver with Windsor Castle

1 Answers