利用配置文件解耦工厂类型

定义一个接口

 public interface IFactory

    {

        IProduct Create();              //  返回默认的 concrete product

        IProduct Create(string name);   //  按照配置的逻辑名称返回指定的concrete product

    }

获取配置类

 public class ProductRegistry

    {

        const string SectionName = "concreteProducts";

        static NameValueCollection collection =

            (NameValueCollection)ConfigurationManager.GetSection(SectionName);



        public Type this[string name]

        {

            get { return Type.GetType(collection[name]); }

        }

    }

工厂

 public class Factory : IFactory

    {



        public const string DefaultName = "DEFAULT";

        public readonly ProductRegistry productRegistry = new ProductRegistry();



        #region IFactory Members



        public IProduct Create()

        {

            return (IProduct)Activator.CreateInstance(productRegistry[DefaultName]);

        }



        public IProduct Create(string name)

        {

            if (string.IsNullOrEmpty(name)) throw new ArgumentNullException("name");

            return (IProduct)Activator.CreateInstance(productRegistry[name]);

        }



        #endregion

    }

page 84，只为自己阅读，复习

 

如果批量生产的话

  public interface IBatchFactory : IFactory

    {

        IEnumerable<IProduct> Create(string name, int quantity);

        IEnumerable<IProduct> Create(int quantity);        

    }

 public class BatchFactory : Factory, IBatchFactory

    {

        #region IBatchFactory Members



        /// <summary>

        /// batch create

        /// </summary>

        /// <param name="quantity"></param>

        /// <returns></returns>

        public IEnumerable<IProduct> Create(int quantity)

        {

            if (quantity <= 0) throw new IndexOutOfRangeException("quantity");

            return InternalCreate<IProduct>(productRegistry[DefaultName], quantity);

        }



        /// <summary>

        /// batch create

        /// </summary>

        /// <param name="name"></param>

        /// <param name="quantity"></param>

        /// <returns></returns>

        public IEnumerable<IProduct> Create(string name, int quantity)

        {

            if (string.IsNullOrEmpty(name)) throw new ArgumentNullException("name");

            return InternalCreate<IProduct>(productRegistry[name], quantity);

        }



        /// <summary>

        /// Helper method

        /// </summary>

        /// <typeparam name="T"></typeparam>

        /// <param name="type"></param>

        /// <param name="quantity"></param>

        /// <returns></returns>

        IEnumerable<T> InternalCreate<T>(Type type, int quantity)

        {

            if (quantity <= 0) throw new IndexOutOfRangeException("quantity");

            if (type == null) throw new ArgumentNullException("type");

            IList<T> result = new List<T>();

            for (int i = 0; i < quantity; i++)

                result.Add((T)Activator.CreateInstance(type));

            return result;

        }



        #endregion

    }