Enterprise Library 5.0中使用Xml文件配置Unity2.0与ServiceLocator

     早在Enterprise Library 5.0之前，就已经有了一个Common Service Locator.在这里假设您对Enterprise Library已经有一定了解。
在Enterprise Library 5.0中，我们通常会使用EnterpriseLibraryContainer.Current，实际上它是IServiceLocator接口。例如下面的代码：

        [TestMethod]
        public void TestGetExceptionManagerFromDefaultEntLibContainer()
        {
            var exceptionManager=
            EnterpriseLibraryContainer.Current.
                GetInstance<Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionManager>();

            Assert.IsNotNull(exceptionManager);
        }

我们从容器中获取一个ExceptionManager的对象.默认也是使用是Unity. 我们可以看这样一段CODE在EnterpriseLibraryContainer类中：

public static IServiceLocator CreateDefaultContainer(IConfigurationSource configurationSource)
{
    IUnityContainer container = new UnityContainer();
    UnityContainerConfigurator configurator = new UnityContainerConfigurator(container);
    ConfigureContainer(configurator, configurationSource);
    return new UnityServiceLocator(container);
}

所以如果您使用xml配置文件来配置Unity，那么就要这样实现：

        [TestMethod]
        public void TestGetExceptionManagerFromServiceLocator()
        {
            // Create the container
            var container = new UnityContainer();

            // Configurator will read Enterprise Library configuration
            // and set up the container
            var configurator = new UnityContainerConfigurator(container);

            // Configuration source holds the new configuration we want to use
            // load this in your own code
            var configSource = new FileConfigurationSource("EntLib.config.xml");

            // Configure the container
            EnterpriseLibraryContainer.CreateDefaultContainer(configSource);

            // Wrap in ServiceLocator
            var locator = new UnityServiceLocator(container);

            // And set Enterprise Library to use it
            EnterpriseLibraryContainer.Current = locator;

            var exceptionManager =
        EnterpriseLibraryContainer.Current.
            GetInstance<Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionManager>();

            Assert.IsNotNull(exceptionManager);
        }

这个地方我们读取一个单独的文件EntLib.config.xml，当时也可用其他方式。但这个方式不能解析自定义的对象。通常我们更愿意直接自定义使用ServiceLocator，如下：

        [TestMethod]
        public void TestGetExceptionManagerFromCustomerServiceLocator()
        {
            var container = new UnityContainer();

            string path = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "EntLib.config.xml");
            var map = new ExeConfigurationFileMap { ExeConfigFilename = path };

            var config
                = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
            var section
                = (UnityConfigurationSection)config.GetSection("unity");
            section.Configure(container, "DefContainer");

            var serviceocator = new UnityServiceLocator(container);

            var exceptionManager = serviceocator.
                GetInstance<Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionManager>();

            Assert.IsNotNull(exceptionManager);
        }

注意，XML需要这样配置，关键在第3行，必须加个extension才能获取EnterpriseLibrary中的Object

  <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <container name="DefContainer">
      <extension type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Unity.EnterpriseLibraryCoreExtension,Microsoft.Practices.EnterpriseLibrary.Common, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
    </container>
  </unity>

下面我们测试一下自定义的Object，XML配置如下:

  <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
    <alias alias="IEmployeeBusinessObject" type="BusinessObject.IEmployeeBusinessObject, BusinessObject" />
    <alias alias="EmployeeBusinessObject" type="BusinessObject.EmployeeBusinessObject, BusinessObject" />
    <container name="DefContainer">
      <extension type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Unity.EnterpriseLibraryCoreExtension,Microsoft.Practices.EnterpriseLibrary.Common, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
      <register  type="IEmployeeBusinessObject" mapTo="EmployeeBusinessObject">
        <lifetime type="singleton" />
      </register >
    </container>
  </unity>

UnitTest, IEmployeeBusinessObject是我们定义的一个Interface。

        [TestMethod]
        public void TestDirectGetCustomerobject()
        {
            var container = new UnityContainer();

            string path = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "EntLib.config.xml");
            var map = new ExeConfigurationFileMap { ExeConfigFilename = path };

            var config
                = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
            var section
                = (UnityConfigurationSection)config.GetSection("unity");
            section.Configure(container, "DefContainer");

            var serviceocator = new UnityServiceLocator(container);

            var employee = serviceocator.GetInstance<IEmployeeBusinessObject>();

            Assert.IsNotNull(employee);
        }


参考：
Creating and Referencing Enterprise Library Objects

希望这篇POST对您开发有帮助。

作者：Petter Liu
出处：http://www.cnblogs.com/wintersun/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
该文章也同时发布在我的独立博客中-Petter Liu Blog。