依赖注入（Autofac）

1.下载autofac压缩包：http://code.google.com/p/autofac/downloads/list

2.解压获得autofac.dll和autofac.configuration.dll文件

依赖注入顾名思义 要存在依赖关系

例如：

   class DataBaseManager
    {
        IDataBase _idatabase;
        public DataBaseManager(IDataBase idatabase)
        {
            
        }
    }

 下面是上图中需要的接口和相应的基类：

 interface IDataBase
    {
        string Name { get;}
        void Select(string commandText);
        void Insert(string commandText);
        void Update(string commandText);
        void Delete(string commandText);
    }
 class SqlDataBase : IDataBase
    {
        public string Name { get { return "sql"; } }
        public void Select(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}",commandText,Name);
        }
        public void Insert(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
        public void Update(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
        public void Delete(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
    }
    class OracleDataBase : IDataBase
    {
        public string Name { get { return "oracel"; } }
        public void Select(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
        public void Insert(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
        public void Update(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
        public void Delete(string commandText)
        {
            Console.WriteLine("'{0}'  is  {1}", commandText, Name);
        }
    }

下面我们在主函数中通过autofac实现简单的注入：

注入前首先要对部分类进行注册 注册的方法有好多种 RegisterInstance RegisterType  Register RegisterMoudle RegisterControllers RegisterAssemblyTypes 我知道的就这些

static void Main(string[] args)
        {          
            var builder = new ContainerBuilder();
            builder.RegisterType<SqlDataBase>().As<IDataBase>();
            //builder.RegisterInstance(new OracelDataBase()).As<IDataBase>();
            //builder.RegisterType<DataBaseManager>();和下面一行的结果相同
              builder.Register(c=>new DataBaseManager(c.Resolve<IDataBase>()));
            using(var container=builder.Build())
            {
                var manager=container.Resolve<DataBaseManager>();
                manager.Select("Select * from database");
            }
            Console.ReadKey();
        }