AutoFac使用方法总结:Part I-白红宇

AutoFac使用方法总结:Part I

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发布时间：2019-06-08

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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]    public void can_resolve_myclass() { var builder = new ContainerBuilder(); builder.RegisterType
          (); IContainer container = builder.Build(); var myClass = container.Resolve
           (); Assert.NotNull(myClass); }
        
     

注册为接口

                       [Fact]    public void register_as_interface() { var builder = new ContainerBuilder(); builder.Register(c => new MyClass()).As
          (); IContainer container = builder.Build(); Assert.NotNull(container.Resolve
           ()); Assert.Throws(typeof (ComponentNotRegisteredException), () => container.Resolve
            ()); }
        
     

使用lambda表达式进行注册

                       [Fact]    public void can_register_with_lambda() { var builder = new ContainerBuilder(); builder.Register(c => new MyClass()); IContainer container = builder.Build(); var myClass = container.Resolve
          (); Assert.NotNull(myClass); }

带构造参数的注册

                       [Fact]    public void register_with_parameter() { var builder = new ContainerBuilder(); builder.Register(c => new MyParameter()); builder.Register(c => new MyClass(c.Resolve
          ())); IContainer container = builder.Build(); Assert.NotNull(container.Resolve
           ()); }
        
     

带属性赋值的注册

                       [Fact]    public void register_with_property() { var builder = new ContainerBuilder(); builder.Register(c => new MyProperty()); builder.Register( c => new MyClass() { Property = c.Resolve
          () }); IContainer container = builder.Build(); var myClass = container.Resolve
           (); Assert.NotNull(myClass); Assert.NotNull(myClass.Property); }
        
     

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]    public void select_an_implementer_based_on_parameter_value() { var builder = new ContainerBuilder(); builder.Register
          ((c, p) => { var type = p.Named
           ("type"); if (type == "test") { return new TestRepository(); } else { return new DbRepository(); } }).As
            (); IContainer container = builder.Build(); var repository = container.Resolve
             (new NamedParameter("type", "test")); Assert.Equal(typeof(TestRepository),repository.GetType()); }
        
     

AufoFac也可以用一个实例来注册，比如用在单例模式情况下：

                       [Fact]    public void register_with_instance() { var builder = new ContainerBuilder(); builder.RegisterInstance(MyInstance.Instance).ExternallyOwned(); IContainer container = builder.Build(); var myInstance1 = container.Resolve
          (); var myInstance2 = container.Resolve
           (); Assert.Equal(myInstance1,myInstance2); }
        
     

注册open generic类型

                       [Fact]    public void register_open_generic() { var builder = new ContainerBuilder(); builder.RegisterGeneric(typeof (MyList<>)); IContainer container = builder.Build(); var myIntList = container.Resolve
           >(); Assert.NotNull(myIntList); var myStringList = container.Resolve
             >(); Assert.NotNull(myStringList); }
        
     

对于同一个接口，后面注册的实现会覆盖之前的实现

                       [Fact]    public void register_order() { var containerBuilder = new ContainerBuilder(); containerBuilder.RegisterType
          ().As
           (); containerBuilder.RegisterType
            ().As
             (); IContainer container = containerBuilder.Build(); var repository = container.Resolve
              (); Assert.Equal(typeof(TestRepository), repository.GetType()); }
        
     

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]    public void register_order_defaults() { var containerBuilder = new ContainerBuilder(); containerBuilder.RegisterType
          ().As
           (); containerBuilder.RegisterType
            ().As
             ().PreserveExistingDefaults(); IContainer container = containerBuilder.Build(); var repository = container.Resolve
              (); Assert.Equal(typeof (DbRepository), repository.GetType()); }
        
     

可以用Name来区分不同的实现，代替As方法

                       [Fact]    public void register_with_name() { var containerBuilder = new ContainerBuilder(); containerBuilder.RegisterType
          ().Named
           ("DB"); containerBuilder.RegisterType
            ().Named
             ("Test"); IContainer container = containerBuilder.Build(); var dbRepository = container.ResolveNamed
              ("DB"); var testRepository = container.ResolveNamed
               ("Test"); Assert.Equal(typeof(DbRepository), dbRepository.GetType()); Assert.Equal(typeof(TestRepository), testRepository.GetType()); }
        
     

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]    public void choose_constructors() { var builder = new ContainerBuilder(); builder.RegisterType
          (); builder.RegisterType
           ().UsingConstructor(typeof (MyParameter)); IContainer container = builder.Build(); var myClass = container.Resolve
            (); Assert.NotNull(myClass); }
        
     

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]    public void register_assembly() { var builder = new ContainerBuilder(); builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()). Where(t => t.Name.EndsWith("Repository")). AsImplementedInterfaces(); IContainer container = builder.Build(); var repository = container.Resolve
          (); Assert.NotNull(repository); }