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。