18、面向对象语言的23种设计模式-迭代器模式

一、什么是迭代器模式

通用的数据集合访问方式。

二、迭代器模式的作用

屏蔽不同集合的构造，提供一个通用的方法对数据集进行访问，就像foreach一样

三、迭代器模式的使用场景

这个.net已经实现的非常好了。。。直接用foreach就好。。

四、如何实现迭代器模式

主程序： 

namespace Iterator
{
    class Program
    {
        static void Main(string[] args)
        {
            {
                MyList deviceModels = new MyList();
                deviceModels.Add(new DeviceModel()
                {
                    Code = 1,
                    Name = "设备1"
                });
                deviceModels.Add(new DeviceModel()
                {
                    Code = 2,
                    Name = "设备2"
                });
                deviceModels.Add(new DeviceModel()
                {
                    Code = 3,
                    Name = "设备3"
                });

                Iiterator iterator = deviceModels.GetIterator();
                while (iterator.MoveNext())
                {
                    DeviceModel device = iterator.Current;
                    Console.WriteLine("Code:{0}，Name:{1}", device.Code, device.Name);
                }
            }
            Console.WriteLine("***********************************************");

            {
                DeviceModel[] deviceModels = new DeviceModel[3];
                deviceModels[0] = new DeviceModel()
                {
                    Code = 1,
                    Name = "设备1"
                };
                deviceModels[1] = new DeviceModel()
                {
                    Code = 2,
                    Name = "设备2"
                };
                deviceModels[2] = new DeviceModel()
                {
                    Code = 3,
                    Name = "设备3"
                };
                MyArray myArray = new MyArray(deviceModels);

                Iiterator iterator = myArray.GetIterator();
                while (iterator.MoveNext())
                {
                    DeviceModel device = iterator.Current;
                    Console.WriteLine("Code:{0}，Name:{1}", device.Code, device.Name);
                }


            }

        }
    }
}

List迭代器： 

//MyList.cs
namespace Iterator
{
    public class MyList
    {
        private List _List = new List();

        public void Add(T model)
        {
            _List.Add(model);
        }

        public List GetList()
        {
            return this._List;
        }

        public Iiterator GetIterator()
        {
            return new MyListIterator(this);
        }
    }
}

//MyListIterator.cs
namespace Iterator
{
    public class MyListIterator : Iiterator
    {
        private List _List = null;

        public MyListIterator(MyList myList)
        {
            this._List = myList.GetList();
        }

        private int _Index = -1;
        public T Current
        {
            get
            {
                return this._List[_Index];
            }
        }

        public bool MoveNext()
        {
            return this._List.Count > ++this._Index;
        }

        public void Reset()
        {
            this._Index = -1;
        }
    }
}

Array迭代器：

//MyArray.cs
namespace Iterator
{
    public class MyArray
    {
        private T[] _Array = null;

        public MyArray(T[] array)
        {
            _Array = array;
        }

        public T[] GetArray()
        {
            return this._Array;
        }

        public Iiterator GetIterator()
        {
            return new MyArrayIterator(this);
        }
    }
}

//MyArrayIterator.cs
namespace Iterator
{
    public class MyArrayIterator: Iiterator
    {
        private T[] _Array = null;

        public MyArrayIterator(MyArray myArray)
        {
            this._Array = myArray.GetArray();
        }

        private int _Index = -1;
        public T Current
        {
            get
            {
                return this._Array[_Index];
            }
        }

        public bool MoveNext()
        {
            return this._Array.Length > ++this._Index;
        }

        public void Reset()
        {
            this._Index = -1;
        }
    }
}

迭代器接口Iiterator.cs：

namespace Iterator
{
    public interface Iiterator
    {
        T Current { get; }

        bool MoveNext();

        void Reset();
    }
}

DeviceModel.cs

namespace Iterator
{
    public class DeviceModel
    {
        public int Code { get; set; }
        public string Name { get; set; }
    }
}

平时还是直接foreach完事。。。要是没有此类功能的话，倒是可以自己写一个。

以上为本章所有内容。

完。