Castle Windsor 3 with constructor argument as string

Question

I have never used Windsor before but have used other DI frameworks, and I have got a rather strange issue at the moment.

I have a factory class which takes a string in its constructor, however whenever I try and resolve that object I get an exception saying:

Handler for System.String was not found.

<Message>Handler for System.String was not found.</Message>
<StackTrace>at Castle.MicroKernel.Resolvers.DefaultDependencyResolver
     .TryGetHandlerFromKernel(DependencyModel dependency, CreationContext context) 
     in d:\60b7fa65294e7792\src\Castle.Windsor\MicroKernel\Resolvers\DefaultDependencyResolver.cs:line 403
at Castle.MicroKernel.Resolvers.DefaultDependencyResolver.ResolveCore(CreationContext context, ComponentModel model, DependencyModel dependency) in d:\60b7fa65294e7792\src\Castle.Windsor\MicroKernel\Resolvers\DefaultDependencyResolver.cs:line 270</StackTrace>
<Type>Castle.MicroKernel.Handlers.HandlerException</Type>
</InnerException>
<Message>Missing dependency.
Component SomeExampleFactory has a dependency on System.String, which could not be 
resolved.
Make sure the dependency is correctly registered in the container as a service, or 
provided as inline argument.</Message>

The class looks something like:

public interface IDummyFactory
{
    void DoSomething();
}

public class DummyFactory : IDummyFactory
{
    private string someString;

    public DummyFactory(string someConstructorArg)
    {
        someString = someConstructorArg;
    }
}

With DI setup below:

var someString = "some constructor arg";
_container.Register(Component.For<IDummyFactory>()
                             .ImplementedBy<DummyFactory>()
                             .DependsOn(someString));

I am assuming it is trying to do some sort of casting or formatting that is causing it to bomb out, but as the type itself is a string, and the variable being passed in a string... it may even be a case that it is trying to map the type of that variable rather than the variable content, but I do not know enough about the DI framework and the documentation around this area

Amylaceous

Which version of Castle Windsor? – Berlinda

Answer 1

Try calling the overload of DependsOn which takes an IDictionary of Key/Value pairs to specify dependencies:

_container.Register(
    Component.For<IDummyFactory>()
        .ImplementedBy<DummyFactory>()
        .DependsOn(new Hashtable 
        { 
            { "someConstructorArg", "some constructor arg" }
        }));

Crookes

Answer 2

I was looking for an answer to this too and it appears like they now have something a little simpler which they call "Inline Dependencies" that is implemented by (among other ways) the Dependency.OnValue() method.

Here is the generic example from the documentation:

var twitterApiKey = @"the key goes here";

 container.Register(
    Component.For<ITwitterCaller>().ImplementedBy<MyTwitterCaller>()
        .DependsOn(Dependency.OnValue("APIKey", twitterApiKey))
    );

It will use the value in twitterApiKey for the paramter that has the name "APIKey" (not case sensitive).

https://github.com/castleproject/Windsor/blob/master/docs/inline-dependencies.md

It looks like this may have gone in as of version 3.1, but I can't quite decipher their update tagging convention.

Remanence