Castle Windsor Property Injection with paramters

Question

I am new to this so I appreciate the help. I am using Castle Windsor as my container with XML config. For several of my core services this works perfectly, I simply declare a public property named the same thing and it injects it as expected. Most of my core services have no-arg constructors, those ones work out of the box. But what about if I have a core service that itself has it's own dependencies, how best to deal with that? For example, say I have a configurable message queuing service:

public interface IQueueService {
    void SendMessage(string msg);
}

public class SQSService : IQueueService {

    private ServiceConfig _config;

    public SQSService(ServiceConfig config) {
        _config = config;
    }

    public void SendMessage(string msg){
        //do message stuff
    }
}

SQSService itself requires a config to initialize properly (endpoint, port, etc). Is there an easy way to configure the DI to resolve this config? Or am I better off re-factoring the SQSService to not have this dependency?

moarboilerplate moarboilerplate · Accepted Answer · 2015-05-12T15:19:25

When injecting something that is dependent on a config, session, request, etc., you have the flexibility to break away from making your dependency object have the same structure as the underlying source (in fact, you should as much as possible, otherwise you may end up accidentally writing code that implicitly depends on that structure). Inject the properties you need, rather than the config itself. I am not sure how to accomplish this using the XML config, but I know the fluent API allows for injection using .FromAppSettings(), or you can use the web/app.config to house your config, using .FromAppConfig() as explained here:

How to instantiate a class based on web.config file with Castle Windsor?

Castle Windsor Property Injection with paramters

1 Answers