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

1 namespace UnityTest
2 {
3     public interface IRun
4     {
5         void Run();
6     }
7 }

1 namespace UnityTest
2 {
3     public class Pet
4     {
5         public string Name { set; get; }
6     }
7 }

 1 using System;
 2 
 3 namespace UnityTest
 4 {
 5     public class Cat : Pet, IRun
 6     {
 7         public void Run()
 8         {
 9             Console.WriteLine("A cat is runing...");
10         }
11     }
12 }

 1 using System;
 2 
 3 namespace UnityTest
 4 {
 5     public class Dog : Pet, IRun
 6     {
 7         public void Run()
 8         {
 9             Console.WriteLine("A dog is runing...");
10         }
11     }
12 }

 1 namespace UnityTest.Model
 2 {
 3     public class Person
 4     {
 5         IRun iRun;
 6 
 7         public Person(IRun iRun)
 8         {
 9             this.iRun = iRun;
10         }
11 
12         public void HiWeGo()
13         {
14             iRun.Run();
15         }
16     }
17 }

 2、创建对象实例

 1 using System;
 2 using System.Web.Script.Serialization;
 3 using Microsoft.Practices.Unity;
 4 
 5 namespace UnityTest
 6 {
 7     class Program
 8     {       
 9         static void Main(string[] args)
10         {
11             var container = new UnityContainer();           
12             container.RegisterType(); //注册类型，并将IRun映射到Dog
13             var dog1 = container.Resolve(); //创建一个IRun实例，实际上就是Dog
14             (dog1 as Dog).Name = "buddy";
15             Console.WriteLine("a dog is born，his name is "{0}"", (dog1 as Dog).Name); //a dog is born，his name is "buddy"
16             Console.Read();
17         }
18     }   
19 }

 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。

1             var container = new UnityContainer();
2             container.RegisterType()
3                     .RegisterType();
4             var run = container.Resolve();//这里的run实例，是cat，还是dog ?
5             Console.Write(run.ToString());//UnityTest.Cat

1             var container = new UnityContainer();
2             container.RegisterType("dogType")
3                     .RegisterType("catType");
4             var run = container.Resolve("dogType");//明确指示，我要一个dog
5             Console.Write(run.ToString());//UnityTest.Dog

 4、创建单例

  1             var container = new UnityContainer();
 2             container.RegisterType("dogTypeSingle", new ContainerControlledLifetimeManager())//dogTypeSingle为单例模式
 3                     .RegisterType("dogType");
 4 
 5             var dog1 = container.Resolve("dogTypeSingle");
 6             var dog2 = container.Resolve("dogTypeSingle");
 7 
 8             Console.WriteLine(object.ReferenceEquals(dog1, dog2));//True
 9             Console.WriteLine(dog1.GetHashCode() == dog2.GetHashCode());//True 说明dog1与dog2是同一个对象
10 
11             var dog3 = container.Resolve("dogType");
12             var dog4 = container.Resolve("dogType");
13             Console.WriteLine(object.ReferenceEquals(dog3, dog4));//False
14             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

1             var container = new UnityContainer();
2             container.RegisterType();
3             var personWithDog = container.Resolve();
4             personWithDog.HiWeGo();//A dog is runing...

 构造器也可以结合标识符显示注入

 1             var container = new UnityContainer();
 2             container.RegisterType("dog")
 3                 .RegisterType("cat")
 4                 .RegisterType("PersonWithDog", new InjectionConstructor(container.Resolve("dog")))
 5                 .RegisterType("PersonWithCat", new InjectionConstructor(container.Resolve("cat")));
 6 
 7             var personWithDog = container.Resolve("PersonWithDog");
 8             personWithDog.HiWeGo();//A dog is runing...
 9             var personWithCat = container.Resolve("PersonWithCat");
10             personWithCat.HiWeGo();//A cat is runing...
11             Console.Read();

 使用InjectionConstructor特性注入

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

1 using System.Collections.Generic;
 2 using Microsoft.Practices.Unity;
 3 namespace UnityTest
 4 {
 5     public class Person
 6     {
 7         private List pets;
 8 
 9         public Person()
10         {
11             pets = new List();
12         }
13 
14         [InjectionConstructor]
15         public Person(IRun iRun):this()
16         {
17             pets.Add(iRun);
18         }
19        
20         public Person(IRun iRun1,IRun iRun2):this()
21         {
22             pets.Add(iRun1);
23             pets.Add(iRun2);
24         }
25 
26 
27         public void HiWeGo()
28         {
29             foreach (var pet in pets)
30             {
31                 pet.Run();
32             }
33         }
34     }
35 }

测试一下：

 1             var container = new UnityContainer();
 2 
 3             container.RegisterType("dog") //注册一个带标识的dog类型
 4                 .RegisterType("cat") //注册一个带标识的cat类型
 5                 .RegisterType() //不指定标识，即默认IRun的实例为dog
 6                 .RegisterType("PersonWithDogAndCat",
 7                     new InjectionConstructor(
 8                         container.Resolve("dog"),
 9                         container.Resolve("cat")
10                     )//显示将二个参数的构造方法注册到容器中
11                 );
12 
13 
14             var person = container.Resolve();//自动调用有InjectionConstructor标记的构造方法
15             person.HiWeGo();//A dog is runing...
16 
17 
18             Console.WriteLine("---------------");
19 
20             var personWithDogAndCat = container.Resolve("PersonWithDogAndCat");//显式调用在容器中注册过的构造方法
21             personWithDogAndCat.HiWeGo();
22             //A dog is runing...
23             //A cat is runing...
24 
25             Console.Read();