Unity 使用快速教程

Unity是微软在CodePlex上的一个开源项目，可用于依赖注入、控制反转，类似Spring，下面是使用示例：

1.先来定义几个接口、类

namespace UnityTest
{
    public interface IRun
    {
        void Run();
    }
}

namespace UnityTest
{
    public class Pet
    {
        public string Name { set; get; }
    }
}

using System;

namespace UnityTest
{
    public class Cat : Pet, IRun
    {
        public void Run()
        {
            Console.WriteLine("A cat is runing...");
        }
    }
}

using System;

namespace UnityTest
{
    public class Dog : Pet, IRun
    {
        public void Run()
        {
            Console.WriteLine("A dog is runing...");
        }
    }
}

namespace UnityTest.Model
{
    public class Person
    {
        IRun iRun;

        public Person(IRun iRun)
        {
            this.iRun = iRun;
        }

        public void HiWeGo()
        {
            iRun.Run();
        }
    }
}

 2、创建对象实例

using System;
using System.Web.Script.Serialization;
using Microsoft.Practices.Unity;

namespace UnityTest
{
    class Program
    {       
        static void Main(string[] args)
        {
            var container = new UnityContainer();           
            container.RegisterType<IRun, Dog>(); //注册类型，并将IRun映射到Dog
            var dog1 = container.Resolve<IRun>(); //创建一个IRun实例，实际上就是Dog
            (dog1 as Dog).Name = "buddy";
            Console.WriteLine("a dog is born，his name is "{0}"", (dog1 as Dog).Name); //a dog is born，his name is "buddy"
            Console.Read();
        }
    }   
}

 3、使用标识符

当IRun同时有多个实例类要注入时，如果没有标识来区别，创建出来的实例“类型”就没办法显示指定。

            var container = new UnityContainer();
            container.RegisterType<IRun, Dog>()
                    .RegisterType<IRun, Cat>();
            var run = container.Resolve<IRun>();//这里的run实例，是cat，还是dog ?
            Console.Write(run.ToString());//UnityTest.Cat

            var container = new UnityContainer();
            container.RegisterType<IRun, Dog>("dogType")
                    .RegisterType<IRun, Cat>("catType");
            var run = container.Resolve<IRun>("dogType");//明确指示，我要一个dog
            Console.Write(run.ToString());//UnityTest.Dog

 4、创建单例

            var container = new UnityContainer();
            container.RegisterType<IRun, Dog>("dogTypeSingle", new ContainerControlledLifetimeManager())//dogTypeSingle为单例模式
                    .RegisterType<IRun, Dog>("dogType");

            var dog1 = container.Resolve<IRun>("dogTypeSingle");
            var dog2 = container.Resolve<IRun>("dogTypeSingle");

            Console.WriteLine(object.ReferenceEquals(dog1, dog2));//True
            Console.WriteLine(dog1.GetHashCode() == dog2.GetHashCode());//True 说明dog1与dog2是同一个对象

            var dog3 = container.Resolve<IRun>("dogType");
            var dog4 = container.Resolve<IRun>("dogType");
            Console.WriteLine(object.ReferenceEquals(dog3, dog4));//False
            Console.WriteLine(dog3.GetHashCode() == dog4.GetHashCode());//False 说明dog3与dog4是不同的对象

 5、依赖注入

构造器自动注入

            var container = new UnityContainer();
            container.RegisterType<IRun, Dog>();
            var personWithDog = container.Resolve<Person>();
            personWithDog.HiWeGo();//A dog is runing...

 构造器也可以结合标识符显示注入

            var container = new UnityContainer();
            container.RegisterType<IRun, Dog>("dog")
                .RegisterType<IRun, Cat>("cat")
                .RegisterType<Person, Person>("PersonWithDog", new InjectionConstructor(container.Resolve<IRun>("dog")))
                .RegisterType<Person, Person>("PersonWithCat", new InjectionConstructor(container.Resolve<IRun>("cat")));

            var personWithDog = container.Resolve<Person>("PersonWithDog");
            personWithDog.HiWeGo();//A dog is runing...
            var personWithCat = container.Resolve<Person>("PersonWithCat");
            personWithCat.HiWeGo();//A cat is runing...
            Console.Read();

 使用InjectionConstructor特性注入

为了演示[InjectionConstructor]特性，先改造一下Person类

using System.Collections.Generic;
using Microsoft.Practices.Unity;
namespace UnityTest
{
    public class Person
    {
        private List<IRun> pets;

        public Person()
        {
            pets = new List<IRun>();
        }

        [InjectionConstructor]
        public Person(IRun iRun):this()
        {
            pets.Add(iRun);
        }
       
        public Person(IRun iRun1,IRun iRun2):this()
        {
            pets.Add(iRun1);
            pets.Add(iRun2);
        }


        public void HiWeGo()
        {
            foreach (var pet in pets)
            {
                pet.Run();
            }
        }
    }
}

测试一下：

            var container = new UnityContainer();

            container.RegisterType<IRun, Dog>("dog") //注册一个带标识的dog类型
                .RegisterType<IRun, Cat>("cat") //注册一个带标识的cat类型
                .RegisterType<IRun, Dog>() //不指定标识，即默认IRun的实例为dog
                .RegisterType<Person, Person>("PersonWithDogAndCat",
                    new InjectionConstructor(
                        container.Resolve<IRun>("dog"),
                        container.Resolve<IRun>("cat")
                    )//显示将二个参数的构造方法注册到容器中
                );


            var person = container.Resolve<Person>();//自动调用有InjectionConstructor标记的构造方法
            person.HiWeGo();//A dog is runing...


            Console.WriteLine("---------------");

            var personWithDogAndCat = container.Resolve<Person>("PersonWithDogAndCat");//显式调用在容器中注册过的构造方法
            personWithDogAndCat.HiWeGo();
            //A dog is runing...
            //A cat is runing...

            Console.Read();

 未完待续...