说在前
Ioc组件有很多，之前也介绍过autofac,castle等，今天再来说一下在微软Nlayer DDD架构里使用的unity组件，今天主要说一下依靠注入，如果希望看拦截的用法，可以阅读这篇文章
做在后
unity的用法主要说一下接口注入方法，它包括了程序中注入和配置文件注入，而接口注入还分为普通接口注入和泛型接口注入，下面分别来说一下：
普通接口和类实现代码
public interface IUser { IQueryable GetEntities(); } public class UserRepository : BackgroundRepository , IUser { public IQueryable GetEntities() { return this.GetModel(); } }
普通接口注入，程序中的注入
using (IUnityContainer container = new UnityContainer()) { container.RegisterType (); var repository = container.Resolve (); } 普通接口注入，配置文件中的注入
using (IUnityContainer container = new UnityContainer()) { ConfigurationManager.GetSection("unity"); UnityConfigurationSection.CurrentSection.Configure(container); var repository = container.Resolve (); } 普通接口和类实现代码
////// 基础的数据操作规范 /// ///public interface IRepository where TEntity : class { /// /// 添加实体并提交到数据服务器 /// /// Item to add to repository void Insert(TEntity item); ////// 移除实体并提交到数据服务器 /// 如果表存在约束，需要先删除子表信息 /// /// Item to delete void Delete(TEntity item); ////// 修改实体并提交到数据服务器 /// /// void Update(TEntity item); ////// 得到指定的实体集合（延时结果集） /// Get all elements of type {T} in repository /// ///List of selected elements IQueryableGetModel(); /// /// 根据主键得到实体 /// /// ///TEntity Find(params object[] id); } public class BackgroundRepository : IRepository where T : class {#region IRepository 成员 public virtual void Insert(TEntity item) { OnBeforeSaved(new SavedEventArgs(item, SaveAction.Insert)); Db.Entry (item); Db.Set ().Add(item); this.SaveChanges(); OnAfterSaved(new SavedEventArgs(item, SaveAction.Insert)); } public virtual void Delete(TEntity item) { OnBeforeSaved(new SavedEventArgs(item, SaveAction.Delete)); Db.Set ().Attach(item); Db.Set ().Remove(item); this.SaveChanges(); OnAfterSaved(new SavedEventArgs(item, SaveAction.Delete)); } public virtual void Update(TEntity item) { OnBeforeSaved(new SavedEventArgs(item, SaveAction.Update)); Db.Set ().Attach(item); Db.Entry(item).State = EntityState.Modified; this.SaveChanges(); OnAfterSaved(new SavedEventArgs(item, SaveAction.Update)); } /// /// 子类在实现时，可以重写，加一些状态过滤 /// ///public virtual IQueryable GetModel() { // return Db.Set ().AsNoTracking();//对象无法自动添加到上下文中，因为它是使用 NoTracking 合并选项检索的。请在定义此关系之前，将该实体显式附加到 ObjectContext。 return Db.Set ();////ObjectStateManager 中已存在具有同一键的对象。ObjectStateManager 无法跟踪具有相同键的多个对象。 } /// /// 得到原生态结果集 /// ///public IQueryable GetEntities() { return Db.Set (); } #endregion ｝
泛型接口注入，程序中的注入
using (IUnityContainer container = new UnityContainer()) { container.RegisterType , BackgroundRepository >(); var re = container.Resolve >(); } 泛型接口注入，配置文件中的注入
using (IUnityContainer container = new UnityContainer()) { ConfigurationManager.GetSection("unity"); UnityConfigurationSection.CurrentSection.Configure(container); var re = container.Resolve >(); } 下面我们封装一个服务定位器，让它把Unity容器封装一下，方便以后调用它，下面是ServiceLocator的原代码：
////// Represents the Service Locator. /// public sealed class ServiceLocator : IServiceProvider { #region Private Fields private readonly IUnityContainer _container; #endregion #region Private Static Fields private static readonly ServiceLocator instance = new ServiceLocator(); #endregion #region Ctor ////// Initializes a new instance of ServiceLocator class. /// private ServiceLocator() { UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity"); _container = new UnityContainer(); section.Configure(_container); } #endregion #region Public Static Properties ////// Gets the singleton instance of the ServiceLocator class. /// public static ServiceLocator Instance { get { return instance; } } #endregion #region Private Methods private IEnumerableGetParameterOverrides(object overridedArguments) { List overrides = new List (); Type argumentsType = overridedArguments.GetType(); argumentsType.GetProperties(BindingFlags.Public | BindingFlags.Instance) .ToList() .ForEach(property => { var propertyValue = property.GetValue(overridedArguments, null); var propertyName = property.Name; overrides.Add(new ParameterOverride(propertyName, propertyValue)); }); return overrides; } #endregion #region Public Methods /// /// Gets the service instance with the given type. /// ///The type of the service. ///The service instance. public T GetService() { return _container.Resolve (); } /// /// Gets the service instance with the given type by using the overrided arguments. /// ///The type of the service. /// The overrided arguments. ///The service instance. public T GetService(object overridedArguments) { var overrides = GetParameterOverrides(overridedArguments); return _container.Resolve (overrides.ToArray()); } /// /// Gets the service instance with the given type by using the overrided arguments. /// /// The type of the service. /// The overrided arguments. ///The service instance. public object GetService(Type serviceType, object overridedArguments) { var overrides = GetParameterOverrides(overridedArguments); return _container.Resolve(serviceType, overrides.ToArray()); } #endregion #region IServiceProvider Members ////// Gets the service instance with the given type. /// /// The type of the service. ///The service instance. public object GetService(Type serviceType) { return _container.Resolve(serviceType); } #endregion }
下面再去使用unity时就方便多了，呵呵，看代码：
var model = ServiceLocator.Instance.GetService>().GetModel().ToList();
而使用ServiceLocator还有一个好处，就是不需要使用＂实现的程序集＂，只要把＂实现的程序集＂和它的相关依赖的程序集一起复制到ＷＥＢ项目的ＢＩＮ目录即可，服务定位器会自己去定位的．
好了，讲到这里也就差不多了，需要注意的是，如果你在项目中进行注入时，需要先注入的实现类所在的程序集也引入进来，否则也是不可以resolve出来对象的，而对于业务层（领域）层来说，不需要关心底层
的实现技术，即不需要引用实现类的程序集，而在业务层引用接口程序集即可．