Unity的依赖注入

Unity允许在构造一个类型实例时对constructor、property、method进行依赖注入。比如ILogger的实现类型MyLogger有一个属性LogWritter，类型是TextWriter。它依赖一个名为LogWriter的类型注册，ILogger和MyLogger的定义如下：

public interface ILogger
{
　　TextWriter LogWriter { get; }
}

public sealed class MyLogger : ILogger
{
　　public TextWriter LogWriter { get; set; }
}

首先注册一个名为LogWriter的类型：

<unity xmlns=”http://schemas.microsoft.com/practices/2010/unity”>
　　<assembly name=”mscorlib, 2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″ />

　　<container>
　　　　<register name=”LogWriter” type=”System.IO.TextWriter” mapTo=”System.IO.StringWriter”>
　　　　　　<constructor />
　　　　</register>
　　</container>
</unity>

再注册ILogger和它的实现：

<register type=”UnityTest3.ILogger, UnityTest3″ mapTo=”UnityTest3.MyLogger, UnityTest3″ />

现在为MyLogger添加property LogWriter的依赖，设置dependencyName为LogWriter、dependencyType为System.IO.TextWriter：

<register type=”UnityTest3.ILogger, UnityTest3″ mapTo=”UnityTest3.MyLogger, UnityTest3″>
　　<property name=”LogWriter” dependencyName=”LogWriter” dependencyType=”System.IO.TextWriter” />
</register>

编写代码获取ILogger：

IUnityContainer unityContainer = new UnityContainer();
unityContainer.LoadConfiguration();

ILogger logger = unityContainer.Resolve<ILogger>();