日期:2014-05-18  浏览次数:21047 次

C# .NET对通用泛型进行快速排序

我们经常使用List<model>泛型进行数据的封装,但是有时候,在某种需求下,你可能需要对这个泛型进行排序,而排序规则是根据model中的某一个属性进行排序,这时棘手的事情来了,怎么办?!!

这个时候我们需要自己扩展一个排序方法,以下我给出一个继承自IComparer接口的类,此类内置好升序和降序的排序规则:

    /// <summary>
    /// 继承IComparer<T>接口,实现同一自定义类型 对象比较
    /// </summary>
    /// <typeparam name="T">T为泛用类型</typeparam>
    public class Reverser<T> : IComparer<T>
    {
        private Type type = null;
        private ReverserInfo info;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="type">进行比较的类类型</param>
        /// <param name="name">进行比较对象的属性名称</param>
        /// <param name="direction">比较方向(升序/降序)</param>
        public Reverser(Type type, string name, ReverserInfo.Direction direction)
        {
            this.type = type;
            this.info.name = name;
            if (direction != ReverserInfo.Direction.ASC)
                this.info.direction = direction;
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="className">进行比较的类名称</param>
        /// <param name="name">进行比较对象的属性名称</param>
        /// <param name="direction">比较方向(升序/降序)</param>
        public Reverser(string className, string name, ReverserInfo.Direction direction)
        {
            try
            {
                this.type = Type.GetType(className, true);
                this.info.name = name;
                this.info.direction = direction;
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
        }


        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="t">进行比较的类型的实例</param>
        /// <param name="name">进行比较对象的属性名称</param>
        /// <param name="direction">比较方向(升序/降序)</param>
        public Reverser(T t, string name, ReverserInfo.Direction direction)
        {
            this.type = t.GetType();
            this.info.name = name;
            this.info.direction = direction;
        }

        //必须!实现IComparer<T>的比较方法。
        int IComparer<T>.Compare(T t1, T t2)
        {
            object x = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t1, null);
            object y = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t2, null);
            if (this.info.direction != ReverserInfo.Direction.ASC)
                Swap(ref x, ref y);
            return (new CaseInsensitiveComparer()).Compare(x, y);
        }

        //交换操作数
        private void Swap(ref object x, ref object y)
        {
            object temp = null;
            temp = x;
            x = y;
            y = temp;
        }
    }

    /// <summary>
    /// 对象比较时使用的信息类
    /// </summary>
    public struct ReverserInfo
    {

        /// <summary>
        /// 比较的方向,如下:
        /// ASC:升序
        /// DESC:降序
        /// </summary>
        public enum Direction
        {
            ASC = 0,
            DESC,
        };

        public enum Target
        {
            CUSTOMER = 0,
            FORM,
            FIELD,
            SERVER,
        };

        public string name;
        public Direction direction;
        public Target target;
    }

 

此时写好后,就只需要知道如何调用就行了:

Reverser<Model> reverser = new Reverser<Model>(typeof(Model), "btnIndex", ReverserInfo.Direction.ASC);

我们通过这样的调用方式,就得到一个定义好的排序规则 reverser,假设我们的泛型实例名为 list,则按照如下调用:

list.Sort(reverser);

至此,就完成了特定的排序规则处理了。