1.引言

上节介绍了,Unity的Lifetime Managers生命周期,Unity具体实现依赖注入包含构造函数注入、属性注入、方法注入,所谓注入相当赋值,下面一个一个来介绍。

2.构造函数注入

Unity利用Resolve方法解析一个对象,都是调用注册类型的构造函数来初始化的,初始化时,Unity能够控制初始化的值,当然,我们要给Unity提供足够的原料,要不然也是巧妇难无米之炊,下面看一些简单的示例。

先准备几个类如下:

    /// <summary>
    /// 班级接口
    /// </summary>
    public interface IClass
    {
        string ClassName { get; set; }

        void ShowInfo();
    }
    /// <summary>
    /// 计科班
    /// </summary>
    public class CbClass : IClass
    {
        public string ClassName { get; set; }

        public void ShowInfo()
        {
            Console.WriteLine("计科班:{0}", ClassName);
        }
    }
    /// <summary>
    /// 电商班
    /// </summary>
    public class EcClass : IClass
    {
        public string ClassName { get; set; }

        public void ShowInfo()
        {
            Console.WriteLine("电商班:{0}", ClassName);
        }
    }

    /// <summary>
    /// 学生接口
    /// </summary>
    public interface IStudent
    {
        string Name { get; set; }
        //就读班级
        void ShowInfo();
    }
    /// <summary>
    /// 学生
    /// </summary>
    public class QlinStudent : IStudent
    {
        public string Name { get; set; }

        private IClass ToClass { get; set; }

        public QlinStudent(IClass _class)
        {
            ToClass = _class;
        }

        public void ShowInfo()
        {
            Console.WriteLine("{0}就读班级:{1}", Name, ToClass.ClassName);
        }
    }

是一个班级和学生的结构,现在我们要解析一个学生IStudent,我们看到具体学生类QlinStudent的构造函数需要一个班级接口,当然要给IUnityContainer容器提供这个班级映射还有学生自己的映射,就你要什么东东,首先要提供IUnityContainer什么东东。

2.1 默认方式

默认方式跟new一个对象,它会根据你提供的材料,选择一个构造函数,即要有构造器要能访问权限,用Public修饰,构造函数的参数也要提供,即IClass也要能解析,不然就报错了,编程注入方式如下:

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();
            //默认注册(无命名),如果后面还有默认注册会覆盖前面的
            container.RegisterType<IClass, CbClass>();
            container.RegisterType<IStudent, QlinStudent>();
            //解析默认对象
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();
        }

配置文件方式 如下:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection,Microsoft.Practices.Unity.Configuration"/>
  </configSections>
  <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <!--引用命名空间-->
    <namespace name="ConsoleApplication1.UnityDemo.Constructor" />
    <!--引用程序集-->
    <assembly name="ConsoleApplication1" />
    <!--容器-->
    <container name="FirstClass">
      <!--映射关系-->
      <register type="IClass"  mapTo="CbClass"></register>
      <register type="IClass" name="ec" mapTo="EcClass"></register>
      <register type="IStudent"  mapTo="QlinStudent">

      </register>
    </container>
  </unity>
</configuration>

 以下是加载配置文件

        public static void ConStructorConfigTest1()
        {
            IUnityContainer container = new UnityContainer();
            string configFile = "http://www.cnblogs.com/UnityDemo/Constructor/Unity.config";
            var fileMap = new ExeConfigurationFileMap { ExeConfigFilename = configFile };
            //从config文件中读取配置信息
            Configuration configuration =
                ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
            //获取指定名称的配置节
            UnityConfigurationSection section = (UnityConfigurationSection)configuration.GetSection("unity");

            //载入名称为FirstClass 的container节点
            container.LoadConfiguration(section, "FirstClass");

            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();
        }

 

2.2 指定构造函数

如果构造函数有多个,它也会按照上面那样来初始化一个对象,我们还可以显示用InjectionConstructor特性来指定一个构造函数来解析对象,如下声明:

    public class QlinStudent : IStudent
    {
        private string Name { get; set; }

        private IClass ToClass { get; set; }


        public QlinStudent()
        {
        }

        [InjectionConstructor]
        public QlinStudent(IClass _class,string name)
        {
            ToClass = _class;
            Name = name;
        }

        public void ShowInfo()
        {
            Console.WriteLine("{0}就读班级:{1}", Name, ToClass.ClassName);
        }
    }

 

2.3 指定参数依赖的注册名称

构造函数中IClass参数,如果IUnityContainer注册了多个,默认是使用无名称的那个注册,也可以通过Dependency依赖哪个名称来指定哪个来注册,代码,指定ec名称如下:

        [InjectionConstructor]
        public QlinStudent([Dependency("ec")]IClass _class)
        {
            ToClass = _class;
        }

下面注册一个名称为ec的映射,如果没有名称ec的映射将报错

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();

            //默认注册(无命名),如果后面还有默认注册会覆盖前面的
            container.RegisterType<IClass, CbClass>();
            //命名注册
            container.RegisterType<IClass, EcClass>("ec");
            container.RegisterType<IStudent, QlinStudent>();

            //解析默认对象
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();
        }

配置文件方式,代码不变,配置中添加一个 name属性就行,如下:

    <container name="FirstClass">
      <!--映射关系-->
      <register type="IClass"  mapTo="CbClass"></register>
      <register type="IClass" name="ec" mapTo="EcClass"></register>
      <register type="IStudent"  mapTo="QlinStudent">
      </register>
    </container>

 

2.4 指定参数值

构造器中的参数也可以依赖一个指定的类型值,如下代码依赖于EcClass类型,可以让构造函数中可以传入一个具体的类型,这也是构造函数传参数,如下:

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();

            //默认注册(无命名),如果后面还有默认注册会覆盖前面的
            container.RegisterType<IClass, CbClass>();
            //命名注册
            container.RegisterType<IClass, EcClass>("ec");
            container.RegisterType<IStudent, QlinStudent>(new InjectionConstructor(new CbClass()));
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();
        }

或者注册一个实例对象,如下:

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();
            IClass cbClass = new CbClass { ClassName="计科051班" };
            //实例注册命名实例
            container.RegisterInstance<IClass>("ec", cbClass);
            container.RegisterType<IStudent, QlinStudent>();
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();
        }

 

配置文件也可以指定类型依赖,如下,指定EcClass:

      <register type="IStudent"  mapTo="QlinStudent">
        <constructor>
          <param name="_class" type="IClass">
            <dependency  type="EcClass"/>
          </param>
        </constructor>
      </register>

上面已经介绍了传参数,是用InjectionConstructor类型,现在构造函数,多一个参数,如下:

        [InjectionConstructor]
        public QlinStudent([Dependency("ec")]IClass _class, string name)
        {
            ToClass = _class;
            Name = name;
        }

多了一个name参数,那必须为容器IUnityContainer提供这个参数,没有这个原材料,它无法构造,就会报错,如下代码:

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();

            container.RegisterType<IStudent, QlinStudent>(new InjectionConstructor(new CbClass() { ClassName = "计科051" }, "Qlin"));
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();           
        }

注入参数后,也可以下次解析的时候,通过ParameterOverrides类来覆盖原来的参数,改变参数值,如下:

        public static void ConStructorCodeTest1()
        {
            IUnityContainer container = new UnityContainer();
            container.RegisterType<IStudent, QlinStudent>(new InjectionConstructor(new CbClass() { ClassName = "计科051" }, "Qlin"));
            IStudent student = container.Resolve<IStudent>();
            student.ShowInfo();

            //覆盖参数解析
            IStudent student1 = container.Resolve<IStudent>(new ParameterOverrides()
                                                               {
                                                                  {"_class",new EcClass(){ ClassName="电商051"}},
                                                                  {"name","linq"}
                                                               });
            student1.ShowInfo();
        }

 

3.属性注入

就是Unity容器解析对象时,为属性赋值,有操作权限要Public修饰属性。属性注入方式和构造函数注入类似,只需在需要注入的属性上增加一个Dependency特性,Dependency指定一个注册名称name参数用来指定注入对象的名称,属性注入也是伴随着类型初始化时注入的,在解析时自动注入,所以解析时跟以前一样。代码修改如下,在ToClass属性上增加了Dependency特性,来表示这个属性需要注入:

    public class QlinStudent : IStudent
    {
        public string Name { get; set; }

        [Dependency("ec")]
        public IClass ToClass { get; set; }

        public void ShowInfo()
        {
            Console.WriteLine("{0}就读班级:{1}", Name, ToClass.ClassName);
        }
    }

代码方式如下:

            IUnityContainer container = new UnityContainer();
            container.RegisterType<IClass, EcClass>("ec");         
            container.RegisterType<IStudent, QlinStudent>();
            IStudent splitClass = container.Resolve<IStudent>();
            splitClass.ShowInfo();

配置文件方式,依赖的<dependency name="ec1" name值 可指定注册时注册的名称:

<unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <!--引用命名空间-->
    <namespace name="ConsoleApplication1.UnityDemo.Constructor4" />
    <!--引用程序集-->
    <assembly name="ConsoleApplication1" />
    <!--容器-->
    <container name="FirstClass">
      <!--映射关系-->
      <register type="IClass"  mapTo="CbClass">      
      </register>
      <register type="IClass" name="ec1" mapTo="EcClass">
        <property name="ClassName" propertyType="System.String" value="电商051" />
      </register>
      <register type="IStudent"  mapTo="QlinStudent">
        <property name="ToClass">
          <dependency name="ec1" type="EcClass"/>
        </property>
      </register>
    </container>
  </unity>

 

调用效果图:

4.方法注入

用public修饰方法,方法注入也是跟构造函数类似代码修改如下

    public class QlinStudent : IStudent
    {
        public string Name { get; set; }

        private IClass ToClass { get; set; }

        [InjectionMethod]
        public void InitClass(IClass _class)
        {
            ToClass = _class;
        }

        public void ShowInfo()
        {
            Console.WriteLine("{0}就读班级:{1}", Name, ToClass.ClassName);
        }
    }

编程方式注入不变,就是初始化时,注入值,如下:

            IUnityContainer container = new UnityContainer();
            container.RegisterType<IClass, EcClass>();         
            container.RegisterType<IStudent, QlinStudent>();
            IStudent student = container.Resolve<IStudent>();
            student.ShowInfo();

配置文件方式:

  <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <!--引用命名空间-->
    <namespace name="ConsoleApplication1.UnityDemo.Constructor5" />
    <!--引用程序集-->
    <assembly name="ConsoleApplication1" />
    <!--容器-->
    <container name="FirstClass">
      <!--映射关系-->
      <register type="IClass"  mapTo="CbClass">      
      </register>
      <register type="IClass" name="ec1" mapTo="EcClass">
        <property name="ClassName" propertyType="System.String" value="电商051" />
      </register>
      <register type="IStudent"  mapTo="QlinStudent">
        <property name="Name" propertyType="System.String" value="Qlin" />
        <method name="InitClass">
          <param name="_class" type="IClass">
            <dependency name="ec1" type="EcClass"/>
          </param>
        </method>
      </register>
    </container>
  </unity>

 

5.小结

 介绍了3种依赖注入方式,平时主要也就用到这么几种,其它还有复杂的像扩展容器等,通过本节,基本知道Unity的使用了。

 

            IUnityContainer container = new UnityContainer();
            //获取指定名称的配置节
            UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");

            //载入名称为FirstClass 的container节点
            container.LoadConfiguration(section, "FirstClass");

            SplitClass splitClass = container.Resolve<SplitClass>();
            splitClass.ShowInfo();
    //分班
    public class SplitClass
    {
        IClass _class;
        IStudent _student;
        
        public SplitClass()
        { }

        [InjectionConstructor]
        public SplitClass([Dependency("ec")]IClass _class, IStudent student)
        {
            this._class = _class;
            _student = student;
            _student.ToClass = this._class;
        }

        public void ShowInfo()
        {
            Console.WriteLine("{0}学生被安排到班级{1}", _student.Name, _class.ClassName);
        }
    }

 

posted on 2012-10-18 10:25  Qlin  阅读(7075)  评论(6编辑  收藏  举报