Comparing Castle Windsor, Unity and StructureMap
In a follow up to Krzysztof’s statement that Windsor does a lot more than other IoC’s, I wanted to understand how these IoC’s stack up against each other and the benefits/additional facilities that castle Windsor provides.
Are there any comparisons? Can someone help me understand the additional features that Castle Windsor provides over other IoC’s
Answer
See here and here for a pretty thorough technical comparison of several IoC containers, although somewhat outdated by now (they're from before Windsor 2.0)
However, I don't think there are really any vital features that Windsor offers and other containers don't. Windsor, StructureMap, Spring.NET have all been around for several years and have been used in lots of projects over these years so they're very mature now. Newer containers, like Autofac, Unity, Ninject and SimpleInjector build on that previous experience so they won't lack those vital features either.
Now the more subjective part of the answer: I like to think that Windsor has a nice mix of usability, extensibility and integration modules.
Usability: for example, you can use XML and/or code registration (it also has a fluent API like most containers nowadays).
Extensibility: Lots of extension points that you can use to customize or override pretty much any default behavior.
Integration: Windsor has lots of facilities (modules) that allow for easy integration with other frameworks/libraries. Other integrations include ASP.NET MVC, MonoRail, Workflow Foundation, NServiceBus, MassTransit, Rhino Service Bus, Quartz.Net, SolrNet, SolrSharp, Windows Fax Services.
This series of articles covers many niceties and extension points of Windsor.
Note that I'm not saying that other containers don't offer similar things! Even if you picked one of them and later you found out it's lacking some integration, it's usually not hard to code it yourself.
Bottom line: I don't think you can go wrong with any of the main IoC containers, as long as you structure your code properly (e.g. avoid the service locator anti-pattern).