using Autofac;

using System;

using System.Reflection;

​

namespace Samples.Autofac.StrategyPattern

{

    public interface IStrategy { void Do(); }

​

    public class ConcreteStrategyA : IStrategy { public void Do() { Console.WriteLine("Called ConcreteStrategyA.Do()"); } };

    public class ConcreteStrategyB : IStrategy { public void Do() { Console.WriteLine("Called ConcreteStrategyB.Do()"); } };

​

    public enum ESomeEnum

    {

        UseStrategyA, UseStrategyB,

    }

​

    public class Context

    {

        private readonly Func<ESomeEnum, IStrategy> _strategyFactory;

​

        public Context(Func<ESomeEnum, IStrategy> strategyFactory)

        {

            _strategyFactory = strategyFactory;

        }

​

        public void DoSomething()

        {

            _strategyFactory(ESomeEnum.UseStrategyB).Do();

            _strategyFactory(ESomeEnum.UseStrategyA).Do();

        }

    }

​

    public class AutofacExample

    {

        public static void Main()

        {

            var builder = new ContainerBuilder();

​

            builder.RegisterType<Context>().AsSelf().SingleInstance();

            builder.RegisterAssemblyTypes(Assembly.GetAssembly(typeof(IStrategy)))

                   .Where(t => typeof(IStrategy).IsAssignableFrom(t))

                   .AsSelf();

            builder.Register<Func<ESomeEnum, IStrategy>>(c =>

            {

                var cc = c.Resolve<IComponentContext>();

                return (someEnum) =>

                {

                    switch (someEnum)

                    {

                        case ESomeEnum.UseStrategyA:

                            return cc.Resolve<ConcreteStrategyA>();

                        case ESomeEnum.UseStrategyB:

                            return cc.Resolve<ConcreteStrategyB>();

                        default:

                            throw new ArgumentException();

                    }

                };

            });

​

            var container = builder.Build();

​

            container.Resolve<Context>().DoSomething();

        }

    }

}