谈到IoC和ASP.NET的集成，很多人会先后想到Ninject，不过我们个人还是倾向于Unity。这篇文章简单地介绍如果创建基于Unity的ControllerFactory。如下面的代码所示，我们通过直接继承DefaultControllerFactory创建一个自定的UnityControllerFactory。构造函数指定的是配置的UnityContainer的名称，如果没有显式指定则采用默认的UnityContainer。在重写的GetControllerInstance方法中，直接调用IUnityContainer的Resolve方法根据Controller类型创建相应的对象。[源代码从这里下载]
1: public class UnityControllerFactory: DefaultControllerFactory
2: {
3: public IUnityContainer Container { get; private set; }
4: public UnityControllerFactory(string containerName = "")
5: {
6: IUnityContainer container = new UnityContainer();
7: UnityConfigurationSection configSection = ConfigurationManager.GetSection(UnityConfigurationSection.SectionName) as UnityConfigurationSection;
8: if (null == configSection && !string.IsNullOrEmpty(containerName))
9: {
10: throw new ConfigurationErrorsException("Cannot find <unity> configuration section");
11: }
12:
13: if (string.IsNullOrEmpty(containerName))
14: {
15: configSection.Configure(container);
16: }
17: else
18: {
19: configSection.Configure(container, containerName);
20: }
21: this.Container = container;
22: }
23: protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
24: {
25: Guard.ArgumentNotNull(controllerType, "controllerType");
26: return (IController)this.Container.Resolve(controllerType);
27: }
28: }
为了演示DefaultControllerFactory的作用，我们来创建一个简单的例子。假设我们要创建一个维护联系人的应用，我们通过具有如下定义的Contact类型表示联系人，而IContactRepository接口定义了一个从存储中获取所有联系人的GetAllContacts方法，DefaultContactRepository是对IContactRepository接口的实现。
1: public class Contact
2: {
3: public string Name { get; set; }
4: public string Gender { get; set; }
5: public string Address { get; set; }
6: }
7:
8: public interface IContactRepository
9: {
10: IEnumerable<Contact> GetAllContacts();
11: }
12:
13: public class DefaultContactRepository : IContactRepository
14: {
15: public IEnumerable<Contact> GetAllContacts()
16: {
17: yield return new Contact
18: {
19: Name = "Zhang San",
20: Gender = "Male",
21: Address = "#328, XingHu Street, Su Zhou, Jiang Su Province, PRC."
22: };
23:
24: yield return new Contact
25: {
26: Name = "Li Si",
27: Gender = "Female",
28: Address = "#328, Jin Ji Hu Road, Su Zhou, Jiang Su Province, PRC."
29: };
30: }
31: }
我们在Web应用的主页显示联系人列表，为此我创建了如下一个HomeController。在这里我们演示的是构造器注入，所以我们通过构造函数指定的IContactRepository对象来初始化Repository属性。在Action方法Index中调用IContactRepository的GetAllContacts方法为对应的View指定Model。
1: public class HomeController : Controller
2: {
3: public IContactRepository Repository { get; private set; }
4: public HomeController(IContactRepository repository)
5: {
6: this.Repository = repository;
7: }
8: public ActionResult Index()
9: {
10: return View(this.Repository.GetAllContacts());
11: }
12: }
Index.cshtml代码如下所示，这是一个Model类型为IEnumerable<Contact>的View，它将所有的联系人信息列出来。
1: @model IEnumerable<Artech.Web.Mvc.Extensions.Contact>
2: @{
3: ViewBag.Title = "Index";
4: }
5:
6: <h2>Contact List</h2>
7:
8: <div>
9: <ul>
10: @foreach (var contact in this.Model)
11: {
12: <li>
13: <h3>@contact.Name</h3>
14: <p>Gender: @contact.Gender</p>
15: <p>Address: @contact.Address</p>
16: <hr />
17: </li>
18: }
19: </ul>
20: </div>
自定义的UnityContainerFactory的注册定义在Gloable.asax中。初次之外，额外需要做的是忽略掉针对favicon.ico的路由，否则程序运行将会失败。
1: public class MvcApplication : System.Web.HttpApplication
2: {
3: public static void RegisterGlobalFilters(GlobalFilterCollection filters)
4: {
5: filters.Add(new HandleErrorAttribute());
6: }
7:
8: public static void RegisterRoutes(RouteCollection routes)
9: {
10: routes.IgnoreRoute("favicon.ico");
11: routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
12: routes.MapRoute("Default", "{controller}/{action}/{id}",
13: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
14: );
15: }
16:
17: protected void Application_Start()
18: {
19: AreaRegistration.RegisterAllAreas();
20: RegisterGlobalFilters(GlobalFilters.Filters);
21: RegisterRoutes(RouteTable.Routes);
22:
23: ControllerBuilder.Current.SetControllerFactory(new UnityControllerFactory());
24: }
25: }
接口IContactRepository和DefualtContactRepository之间的映射关系定义在如下所示的<unity>配置中。
1: <unity>
2: <alias alias="IContactRepository" type="Artech.Web.Mvc.Extensions.IContactRepository, UnityIntegration" />
3: <alias alias="DefaultContactRepository" type="Artech.Web.Mvc.Extensions.DefaultContactRepository, UnityIntegration" />
4: <container>
5: <register type="IContactRepository" mapTo="DefaultContactRepository"/>
6: </container>
7: </unity>
通过浏览器访问Web应用的主页，将会得到如下所示的联系人列表。
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