在 Controller 中使用 构造函数进行依赖注入 (IoC)
1. Controller 代码：
ICard card;
ICardCategory cardCategory;
public CardController(ICard card, ICardCategory cardCategory)
{
this.card = card;
this.cardCategory = cardCategory;
}
接口 ICard , ICardCateogry 是一个普通的接口，没有继承或实现任何接口，而需要做的就是在 Gloable.cs 文件中解析依赖， 为了方便复用，将解析依赖封装成一个类，然后在 Gloable.cs 文件中注册，在这个示例中，使用的是 Unity 进行依赖注入，完整的代码如下：
using Microsoft.Practices.Unity;
using System;
using System.Collections.Generic;
//using System.Web.Http.Dependencies;
using System.Web;
using System.Web.Mvc; namespace SnsManage.Resolver
{
/// <summary>
/// Dependency Injection Resolver Container
/// </summary>
public class UnityResolver : IDependencyResolver
{
protected IUnityContainer container; public UnityResolver(IUnityContainer container)
{
if (container == null)
{
throw new ArgumentNullException("container");
}
this.container = container;
} public object GetService(Type serviceType)
{
try
{
return container.Resolve(serviceType);
}
catch (ResolutionFailedException)
{
return null;
}
} public IEnumerable<object> GetServices(Type serviceType)
{
try
{
return container.ResolveAll(serviceType);
}
catch (ResolutionFailedException)
{
return new List<object>();
}
} //public IDependencyScope BeginScope()
//{
// var child = container.CreateChildContainer();
// return new UnityResolver(child);
//} //public void Dispose()
//{
// container.Dispose();
//} //private const string HttpContextKey = "perRequestContainer"; //private readonly IUnityContainer container; //public UnityResolver(IUnityContainer container)
//{
// this.container = container;
//} //public object GetService(Type serviceType)
//{
// if (typeof(IController).IsAssignableFrom(serviceType))
// {
// return ChildContainer.Resolve(serviceType);
// } // return IsRegistered(serviceType) ? ChildContainer.Resolve(serviceType) : null;
//} //public IEnumerable<object> GetServices(Type serviceType)
//{
// if (IsRegistered(serviceType))
// {
// yield return ChildContainer.Resolve(serviceType);
// } // foreach (var service in ChildContainer.ResolveAll(serviceType))
// {
// yield return service;
// }
//} //protected IUnityContainer ChildContainer
//{
// get
// {
// var childContainer = HttpContext.Current.Items[HttpContextKey] as IUnityContainer; // if (childContainer == null)
// {
// HttpContext.Current.Items[HttpContextKey] = childContainer = container.CreateChildContainer();
// } // return childContainer;
// }
//} //public static void DisposeOfChildContainer()
//{
// var childContainer = HttpContext.Current.Items[HttpContextKey] as IUnityContainer; // if (childContainer != null)
// {
// childContainer.Dispose();
// }
//} //private bool IsRegistered(Type typeToCheck)
//{
// var isRegistered = true; // if (typeToCheck.IsInterface || typeToCheck.IsAbstract)
// {
// isRegistered = ChildContainer.IsRegistered(typeToCheck); // if (!isRegistered && typeToCheck.IsGenericType)
// {
// var openGenericType = typeToCheck.GetGenericTypeDefinition(); // isRegistered = ChildContainer.IsRegistered(openGenericType);
// }
// } // return isRegistered;
//}
}
}
然后在 App_Start 文件中添加一个配置类， UnityConfig.cs, 其中的代码如下：
public static class UnityConfig
{
/// <summary>
/// Dependency Injection
/// </summary>
public static void RegisterComponents()
{
var container = new UnityContainer(); // register all your components with the container here
// it is NOT necessary to register your controllers // e.g. container.RegisterType<ITestService, TestService>(); container.RegisterType<IUser, UserService>( new HierarchicalLifetimeManager()); DependencyResolver.SetResolver(new UnityResolver(container)); }
}
最后在 Global.asax 文件中注册
UnityConfig.RegisterComponents();