接口注入

public interface ITimeProvider
    {
        DateTime CurrentDate { get; }
    }
    public interface IobjectWithTimeProvider
    {
        ITimeProvider TimeProvider { get; set; }
    }
    public class TimeProvider : ITimeProvider
    {
        public DateTime CurrentDate { get { return DateTime.Now; } }
    }

    //下面实现这个Assembler
    public class Assembler
    {
        static Dictionary<Type, Type> dictionary = new Dictionary<Type, Type>();
        static Assembler()
        {
            dictionary.Add(typeof(ITimeProvider), typeof(TimeProvider));
        }

        public object Creat(Type type)
        {
            if ((type == null) || !dictionary.ContainsKey(type))
                throw new NullReferenceException();
            return Activator.CreateInstance(dictionary[type]);
        }

        //泛型方式调用
        public T Creat<T>()
        {
            return (T)Creat(typeof(T));
        }
    }

    public class Client : IobjectWithTimeProvider
    {
       public ITimeProvider TimeProvider { get; set; }
    }

 [TestClass()]
    public class ClientTest
    {

        [TestMethod]
        public void Test()
        {
            ITimeProvider timeprovider = (new Assembler()).Creat<ITimeProvider>();
            IobjectWithTimeProvider objectprovider = new Client();
            objectprovider.TimeProvider = timeprovider;
        }
       
    }

与值注入有点类似，客户端去实现这个接口，这样客户端就可以获得类型，然后通过Assembler实现再通过赋值的形式注入