CodeCaster、Noctis 和 Cristiano 感谢您的所有帮助和指导。我刚刚得到了上述查询的解决方案 -
第一步是使用 nuget在WebApi解决方案中安装Windsor.Castle包。
考虑以下代码片段 -
接口IWatch.cs
public interface IWatch
{
DateTime GetTime();
}
类Watch.cs
public class Watch:IWatch
{
public DateTime GetTime()
{
return DateTime.Now;
}
}
ApiController WatchController.cs定义如下： -
public class WatchController : ApiController
{
private readonly IWatch _watch;
public WatchController(IWatch watch)
{
_watch = watch;
}
public string Get()
{
var message = string.Format("The current time on the server is: {0}", _watch.GetTime());
return message;
}
}
在控制器中，我们通过 WatchController 构造函数中的 IWatch 对象注入了依赖项。我已经使用IDependencyResolver和IDependencyScope来实现 web api 中的依赖注入。IDependencyResolver 接口用于解析请求范围之外的所有内容。
WindsorDependencyResolver.cs
internal sealed class WindsorDependencyResolver : IDependencyResolver
{
private readonly IWindsorContainer _container;
public WindsorDependencyResolver(IWindsorContainer container)
{
if (container == null)
{
throw new ArgumentNullException("container");
}
_container = container;
}
public object GetService(Type t)
{
return _container.Kernel.HasComponent(t) ? _container.Resolve(t) : null;
}
public IEnumerable<object> GetServices(Type t)
{
return _container.ResolveAll(t).Cast<object>().ToArray();
}
public IDependencyScope BeginScope()
{
return new WindsorDependencyScope(_container);
}
public void Dispose()
{
}
}
WindsorDependencyScope.cs
internal sealed class WindsorDependencyScope : IDependencyScope
{
private readonly IWindsorContainer _container;
private readonly IDisposable _scope;
public WindsorDependencyScope(IWindsorContainer container)
{
if (container == null)
{
throw new ArgumentNullException("container");
}
_container = container;
_scope = container.BeginScope();
}
public object GetService(Type t)
{
return _container.Kernel.HasComponent(t) ? _container.Resolve(t) : null;
}
public IEnumerable<object> GetServices(Type t)
{
return _container.ResolveAll(t).Cast<object>().ToArray();
}
public void Dispose()
{
_scope.Dispose();
}
}
WatchInstaller.cs
安装程序只是实现IWindsorInstaller接口的类型。该接口有一个名为 Install 的方法。该方法获取容器的一个实例，然后它可以使用流畅的注册 API 注册组件：
public class WatchInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container, IConfigurationStore store)
{
//Need to Register controllers explicitly in your container
//Failing to do so Will receive Exception:
//> An error occurred when trying to create //a controller of type
//> 'xxxxController'. Make sure that the controller has a parameterless
//> public constructor.
//Reason::Basically, what happened is that you didn't register your controllers explicitly in your container.
//Windsor tries to resolve unregistered concrete types for you, but because it can't resolve it (caused by an error in your configuration), it return null.
//It is forced to return null, because Web API forces it to do so due to the IDependencyResolver contract.
//Since Windsor returns null, Web API will try to create the controller itself, but since it doesn't have a default constructor it will throw the "Make sure that the controller has a parameterless public constructor" exception.
//This exception message is misleading and doesn't explain the real cause.
container.Register(Classes.FromThisAssembly()
.BasedOn<IHttpController>()
.LifestylePerWebRequest());***
container.Register(
Component.For<IWatch>().ImplementedBy<Watch>()
);
}
}
最后，我们需要用 Global.asax.cs（Application_Start 方法）中的 Windsor 实现替换默认的依赖解析器并安装我们的依赖：
private static IWindsorContainer _container;
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
ConfigureWindsor(GlobalConfiguration.Configuration);
}
public static void ConfigureWindsor(HttpConfiguration configuration)
{
_container = new WindsorContainer();
_container.Install(FromAssembly.This());
_container.Kernel.Resolver.AddSubResolver(new CollectionResolver(_container.Kernel, true));
var dependencyResolver = new WindsorDependencyResolver(_container);
configuration.DependencyResolver = dependencyResolver;
}