Lind.DDD.Domain.ISortBehavor～上移与下移

class Entity { public int ID{ get; set; } }

interface ISortBehavor { int SortNumber{ get; set; } }

而上移与下移我们使用一个泛型方法来接收参数，这样扩展性更好一些，开发人员只要把需要上下移的集合传到方法里，之后你的集合就可以被排序，当然这里面会进行各个元素的移动操作！

    class Extenstion
    {
        /// <summary>
        /// Sortable the specified list, id and newSort.
        /// </summary>
        /// <param name=‘list‘>
        /// List.
        /// </param>
        /// <param name=‘id‘>
        /// Identifier.
        /// </param>
        /// <param name=‘newSort‘>
        /// New sort.
        /// </param>
        /// <typeparam name=‘T‘>
        /// The 1st type parameter.
        /// </typeparam>
        public static void Sortable<T> (List<T> list, int id, int newSort) where T:class
        {

            var old = list.Find (i => (i as Entity).ID == id);
            if (old == null || (old as ISortBehavor).SortNumber == newSort)
                return;


            if ((old as  ISortBehavor).SortNumber > newSort) {
                (old as ISortBehavor).SortNumber = newSort;

                foreach (ISortBehavor item in    list.FindAll(i=>(i as Entity).ID!=id && (i as ISortBehavor).SortNumber>=newSort)) {

                    item.SortNumber += 1;
                }
            
            } else {
                (old as ISortBehavor).SortNumber = newSort;

            
                foreach (ISortBehavor item in    list.FindAll(i=>(i as Entity).ID!=id && (i as ISortBehavor).SortNumber<=newSort)) {

                    item.SortNumber -= 1;
                }
            }
            list.ForEach (i => {

                Console.WriteLine ((i as Entity).ID + "sort:" + (i as ISortBehavor).SortNumber);
            }
            );
        }
    }

我们测试一下程序，看一下神奇的结果

    class MainClass
    {
        public static void Main (string[] args)
        {
            List<Person> list = new List<Person> ();
            list.Add (new Person {ID=1,Name="zzl",SortNumber=1});
            list.Add (new Person {ID=2,Name="zzl2",SortNumber=2});
            list.Add (new Person {ID=3,Name="zzl3",SortNumber=3});

            Console.WriteLine ("Hello World!");
            Extenstion.Sortable (list, 1, 2);
            Extenstion.Sortable (list, 2, 3);

        }
    }