《轉》IOC容器特性注入第二篇：初始引擎尋找對應的IOC容器

標籤：

上篇文章介紹了如何利用反射類尋找網站bin檔案夾下面所有DLL的程式集類，這篇文章將介紹如何初始化一個IOC容器引擎。

目前IOC容器有很多，如Ninject,Autofac等，每個容器的驅動都不一樣，為了方便驅動解耦，好使用不同的IOC容器，就得有一個公用介面。

1. IEngine （引擎介面）

    public interface IEngine {        //#region Initialize        //void Initialize();        //#endregion        #region ContainerManager        IContainerManger ContainerManager { get; }        #endregion        #region Resolve        T Resolve<T>(params Parameter[] parameters) where T : class;        T Resolve<T>(string name, params Parameter[] parameters) where T : class;        object Resolve(Type type, params Parameter[] parameters);        object Resolve(Type type, string name, params Parameter[] parameters);        #endregion        #region TryResolve        T TryResolve<T>(params Parameter[] parameters) where T : class;        T TryResolve<T>(string name, params Parameter[] parameters) where T : class;        object TryResolve(Type type, params Parameter[] parameters);        object TryResolve(Type type, string name, params Parameter[] parameters);        #endregion        #region ResolveAll        IEnumerable<Object> ResolveAll(Type serviceType);        IEnumerable<T> ResolveAll<T>();        #endregion    }

介面主要約束：解析，試圖解析，解析所有三個方法，都採用執行個體和泛型兩個版本來寫。PS：泛型就是執行個體的約束版而已，但線程是安全的。

2.EngineContext（引擎上下文）

    public class EngineContext {        #region Initializtion Methods        /// <summary>        /// 確保方法同步執行個體化        /// </summary>        /// <param name="forceRecreate"></param>        /// <returns></returns>        [MethodImpl(MethodImplOptions.Synchronized)]        public static IEngine Initialize(bool forceRecreate)        {            if (Singleton<IEngine>.Instance == null || forceRecreate)            {                Singleton<IEngine>.Instance = CreateEngineInstance();                //Singleton<IEngine>.Instance.Initialize();            }            return Singleton<IEngine>.Instance;        }        #endregion        public static IEngine CreateEngineInstance()        {            var typeFinder = new WebAppTypeFinder();            var engines = typeFinder.FindClassesOfType<IEngine>().ToArray();            if (engines.Length > 0)            {                var defaultEngine =(IEngine)Activator.CreateInstance(engines[0]);                return defaultEngine;            }            else            {                throw  new ApplicationException("找不到IOC容器");            }        }        public static IEngine Current        {            get            {                if (Singleton<IEngine>.Instance == null)                {                    Initialize(false);                }                return Singleton<IEngine>.Instance;            }        }    }

引擎上下文：為了保證系統線程當中可以高效能的使用容器驅動，又是唯一的執行個體，所以使用單例類進行託管

3.Singleton（單列類）

/// <summary>    /// 單列模式保持唯一性 提高效能    /// </summary>    public class Singleton    {        /// <summary>        /// 字典數組        /// </summary>        private static readonly IDictionary<Type, object> allSingletons;         static Singleton()        {            allSingletons=new Dictionary<Type, object>();        }        public static IDictionary<Type, object> AllSingletons        {            get            {                return allSingletons;            }        }    }    /// <summary>    /// 單列泛型模式    /// </summary>    /// <typeparam name="T"></typeparam>    public class Singleton<T> : Singleton    {        private static T _instance;        public static T Instance        {            get            {                return _instance;            }            set            {                _instance = value;                AllSingletons[typeof (T)] = value;            }        }    }    /// <summary>    /// 單列泛型數組模式    /// </summary>    /// <typeparam name="T"></typeparam>    public class SingletonList<T> : Singleton<IList<T>>    {        static SingletonList()        {            Singleton<IList<T>>.Instance=new List<T>();        }        public new static IList<T> Instance        {            get            {                return Singleton<IList<T>>.Instance;            }        }     }    /// <summary>    /// 單列字典模式    /// </summary>    /// <typeparam name="TKey"></typeparam>    /// <typeparam name="TValue"></typeparam>    public class SingletonDictionary<TKey, TValue> : Singleton<IDictionary<TKey, TValue>>    {        static SingletonDictionary()        {            Singleton<Dictionary<TKey,TValue>>.Instance=new Dictionary<TKey, TValue>();        }        public new static IDictionary<TKey, TValue> Instance        {            get            {                return Singleton<Dictionary<TKey, TValue>>.Instance;            }        }    }

單例類：防止重複建立執行個體。

上面主要是容器介面，上下文等封裝，要使用具體的IOC那就得繼承IEngine這個介面。

這裡使用的是Ninject介面類：

4.NinjectEngine(實現IEngine介面)

public class NinjectEngine:IEngine {        #region Properties        public IContainerManger ContainerManager        {            get;            private set;        }        public ITypeFinder TypeFinder        {            get;            private set;        }        #endregion        #region .ctor        public NinjectEngine(ITypeFinder typeFinder):this(typeFinder,new ContainerManager())        {}        public NinjectEngine(ITypeFinder typeFinder, ContainerManager containerManager)        {            if (typeFinder == null)            {                throw  new ArgumentException("沒有反射類尋找器");            }            this.TypeFinder = typeFinder;            this.ContainerManager = containerManager;            InitializeContainer();        }        #endregion        #region Methods        private void InitializeContainer() {            var attrDependency = new DependencyAttributeRegistrator(this.TypeFinder, this.ContainerManager);            attrDependency.RegisterServices();        }        public T Resolve<T>(params Parameter[] parameters) where T : class        {            return ContainerManager.Resolve<T>(null, parameters);        }        public T Resolve<T>(string name, params Parameter[] parameters) where T : class        {            return ContainerManager.Resolve<T>(name, parameters);        }        public object Resolve(Type type, params Parameter[] parameters)        {            return ContainerManager.Resolve(type, null, parameters);        }        public object Resolve(Type type, string name, params Parameter[] parameters) {            return ContainerManager.Resolve(type, name, parameters);        }        public T TryResolve<T>(params Parameter[] parameters) where T : class        {            return ContainerManager.TryResolve<T>(null, parameters);        }        public T TryResolve<T>(string name, params Parameter[] parameters) where T : class        {            return ContainerManager.TryResolve<T>(name, parameters);        }        public object TryResolve(Type type, params Parameter[] parameters)        {            return ContainerManager.TryResolve(type, null, parameters);        }        public object TryResolve(Type type, string name, params Parameter[] parameters)        {            return ContainerManager.TryResolve(type, name, parameters);        }        public IEnumerable<object> ResolveAll(Type serviceType)        {            return ContainerManager.ResolveAll(serviceType);        }        public IEnumerable<T> ResolveAll<T>()        {            return ContainerManager.ResolveAll<T>();        }        #endregion    }

引擎初始化大致過程是這樣的。介面=>程式集尋找=>實現介面的IOC容器類=>寫入單列=>形成容器驅動上下文

《轉》IOC容器特性注入第二篇：初始引擎尋找對應的IOC容器