Unity Ioc框架简单例子

IOC:英文全称：Inversion of Control，中文名称：控制反转，它还有个名字叫依赖注入（Dependency Injection）。
作用：将各层的对象以松耦合的方式组织在一起，解耦，各层对象的调用完全面向接口。当系统重构的时候，代码的改写量将大大减少。
理解依赖注入：

引入Unity：http://unity.codeplex.com/

或者VS GuGet中引用

Dependency 属性注入需要填特性

InjectionMethod 方法注入需要添加特性

    public interface IA { }
    public interface IB { }
    public interface IC { }
    public interface ID { }

    public class A : IA
    {
        public IB B { get; set; }
        [Dependency]
        public IC C { get; set; }
        public ID D { get; set; }

        public A(IB b)
        {
            this.B = b;
        }
        [InjectionMethod]
        public void Initialize(ID d)
        {
            this.D = d;
        }
    }
    public class B : IB { }
    public class C : IC { }
    public class D : ID { }

代码方式注册：

 static void Main(string[] args)
        {
            // http://unity.codeplex.com/

             IUnityContainer container = new UnityContainer(); //注册映射
             container.RegisterType<IA, A>();
             container.RegisterType<IB, B>();
             container.RegisterType<IC, C>();
             container.RegisterType<ID, D>();

            //得到A的实例
             A a = (A)container.Resolve<IA>();

             Console.WriteLine("a.B == null ? {0}", a.B == null ? "Yes" : "No");
             Console.WriteLine("a.C == null ? {0}", a.C == null ? "Yes" : "No");
             Console.WriteLine("a.D == null ? {0}", a.D == null ? "Yes" : "No");

            Console.Read();
        }

配置文件方式注册：

<configuration>
  <configSections>
    <section name="unity"
        type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection,Microsoft.Practices.Unity.Configuration"/>
  </configSections>
  <unity>
    <containers>
      <container>
        <register type="Client.IA, Client" mapTo="Client.A, Client"/>
        <register type="Client.IB, Client" mapTo="Client.B, Client"/>
        <register type="Client.IC, Client" mapTo="Client.C, Client"/>
        <register type="Client.ID, Client" mapTo="Client.D, Client"/>
      </container>
    </containers>
  </unity>

</configuration>

　　

 static void Main(string[] args)
        {
            // http://unity.codeplex.com/
             IUnityContainer container = new UnityContainer();
             UnityConfigurationSection configuration = (UnityConfigurationSection)ConfigurationManager.GetSection(UnityConfigurationSection.SectionName);
             configuration.Configure(container);
             A a = (A)container.Resolve<IA>();

             Console.WriteLine("a.B == null ? {0}", a.B == null ? "Yes" : "No");
             Console.WriteLine("a.C == null ? {0}", a.C == null ? "Yes" : "No");
             Console.WriteLine("a.D == null ? {0}", a.D == null ? "Yes" : "No");

            Console.Read();
        }