AutoFac使用方法总结一：注册

AutoFac是.net平台下的IOC容器产品，它可以管理类之间的复杂的依赖关系。在使用方面主要是register和resolve两类操作。 这篇文章用单元测试的形式列举了AutoFac的常用使用方法：

注册部分

使用RegisterType进行注册

 [Fact]  2     public void can_resolve_myclass()  3  {  4         var builder = new ContainerBuilder();  5         builder.RegisterType<MyClass>();  6 
        IContainer container = builder.Build();  8         var myClass = container.Resolve<MyClass>();  9  Assert.NotNull(myClass); 10     }

注册为接口

 [Fact]  2     public void register_as_interface()  3  {  4         var builder = new ContainerBuilder();  5         builder.Register(c => new MyClass()).As<MyInterface>();  6 
        IContainer container = builder.Build();  8         Assert.NotNull(container.Resolve<MyInterface>());  9         Assert.Throws(typeof (ComponentNotRegisteredException), () => container.Resolve<MyClass>()); 10     }

使用lambda表达式进行注册

 [Fact]  2     public void can_register_with_lambda()  3  {  4         var builder = new ContainerBuilder();  5         builder.Register(c => new MyClass());  6 
        IContainer container = builder.Build();  8         var myClass = container.Resolve<MyClass>();  9  Assert.NotNull(myClass); 10     }

带构造参数的注册

 [Fact] 2     public void register_with_parameter() 3  { 4         var builder = new ContainerBuilder(); 5         builder.Register(c => new MyParameter()); 6         builder.Register(c => new MyClass(c.Resolve<MyParameter>())); 7         IContainer container = builder.Build(); 8         Assert.NotNull(container.Resolve<MyClass>()); 9     }  

带属性赋值的注册

 [Fact]  2     public void register_with_property()  3  {  4         var builder = new ContainerBuilder();  5         builder.Register(c => new MyProperty());  6  builder.Register(  7             c => new MyClass()  8  {  9                          Property = c.Resolve<MyProperty>() 10  }); 11         IContainer container = builder.Build(); 12         var myClass = container.Resolve<MyClass>(); 13  Assert.NotNull(myClass); 14  Assert.NotNull(myClass.Property); 15     }  

Autofac分离了类的创建和使用，这样可以根据输入参数（NamedParameter）动态的选择实现类。

 [Fact]  2     public void select_an_implementer_based_on_parameter_value()  3  {  4         var builder = new ContainerBuilder();  5         builder.Register<IRepository>((c, p) =>
 {  7                                  var type = p.Named<string>("type");  8                                  if (type == "test")  9  { 10                                      return new TestRepository(); 11  } 12                                  else
 { 14                                      return new DbRepository(); 15  } 16                              }).As<IRepository>(); 17 
        IContainer container = builder.Build(); 19         var repository = container.Resolve<IRepository>(new NamedParameter("type", "test")); 20         Assert.Equal(typeof(TestRepository),repository.GetType()); 21     }

AufoFac也可以用一个实例来注册，比如用在单例模式情况下：

 [Fact]  2     public void register_with_instance()  3  {  4         var builder = new ContainerBuilder();  5  builder.RegisterInstance(MyInstance.Instance).ExternallyOwned();  6         IContainer container = builder.Build();  7         var myInstance1 = container.Resolve<MyInstance>();  8         var myInstance2 = container.Resolve<MyInstance>();  9  Assert.Equal(myInstance1,myInstance2); 10     }

注册open generic类型

 [Fact]  2     public void register_open_generic()  3  {  4         var builder = new ContainerBuilder();  5         builder.RegisterGeneric(typeof (MyList<>));  6         IContainer container = builder.Build();  7         var myIntList = container.Resolve<MyList<int>>();  8  Assert.NotNull(myIntList);  9         var myStringList = container.Resolve<MyList<string>>(); 10  Assert.NotNull(myStringList); 11     }

对于同一个接口，后面注册的实现会覆盖之前的实现

 [Fact]  2     public void register_order()  3  {  4         var containerBuilder = new ContainerBuilder();  5         containerBuilder.RegisterType<DbRepository>().As<IRepository>();  6         containerBuilder.RegisterType<TestRepository>().As<IRepository>();  7 
        IContainer container = containerBuilder.Build();  9         var repository = container.Resolve<IRepository>(); 10         Assert.Equal(typeof(TestRepository), repository.GetType()); 11     }

如果不想覆盖的话，可以用PreserveExistingDefaults，这样会保留原来注册的实现。

 [Fact]  2     public void register_order_defaults()  3  {  4         var containerBuilder = new ContainerBuilder();  5         containerBuilder.RegisterType<DbRepository>().As<IRepository>();  6         containerBuilder.RegisterType<TestRepository>().As<IRepository>().PreserveExistingDefaults();  7 
        IContainer container = containerBuilder.Build();  9         var repository = container.Resolve<IRepository>(); 10         Assert.Equal(typeof (DbRepository), repository.GetType()); 11     }

可以用Name来区分不同的实现，代替As方法

 [Fact]  2     public void register_with_name()  3  {  4         var containerBuilder = new ContainerBuilder();  5         containerBuilder.RegisterType<DbRepository>().Named<IRepository>("DB");  6         containerBuilder.RegisterType<TestRepository>().Named<IRepository>("Test");  7 
        IContainer container = containerBuilder.Build();  9         var dbRepository = container.ResolveNamed<IRepository>("DB"); 10         var testRepository = container.ResolveNamed<IRepository>("Test"); 11         Assert.Equal(typeof(DbRepository), dbRepository.GetType()); 12         Assert.Equal(typeof(TestRepository), testRepository.GetType()); 13     }

如果一个类有多个构造函数的话，可以在注册时候选择不同的构造函数

 [Fact]  2     public void choose_constructors()  3  {  4         var builder = new ContainerBuilder();  5         builder.RegisterType<MyParameter>();  6         builder.RegisterType<MyClass>().UsingConstructor(typeof (MyParameter));  7         IContainer container = builder.Build();  8         var myClass = container.Resolve<MyClass>();  9  Assert.NotNull(myClass); 10     }

AutoFac可以注册一个Assemble下所有的类，当然，也可以根据类型进行筛选

 [Fact]  2     public void register_assembly()  3  {  4         var builder = new ContainerBuilder();  5  builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).  6             Where(t => t.Name.EndsWith("Repository")).  7  AsImplementedInterfaces();  8 
        IContainer container = builder.Build(); 10         var repository = container.Resolve<IRepository>(); 11  Assert.NotNull(repository); 12     }

 

参考链接：http://niuyi.github.io/blog/2012/04/06/autofac-by-unit-test/