1 using System;
  2 using System.Collections.Generic;
  3 
  4 namespace DesignPattern
  5 {
  6     class Program
  7     {
  8         public static readonly string[] OrderStrings =
  9         {
 10             nameof(Square),
 11             nameof(Triangle),
 12             nameof(Circle), 
 13             null
 14         };
 15 
 16         static void Main(string[] args)
 17         {
 18             // 产生若干个随机图形
 19             Random random = new Random();
 20             var shapes = new List<Shape>();
 21             for (int i = 0; i < 100; i++)
 22             {
 23                 var value = random.Next(0, 15);
 24                 if (value < 5)
 25                 {
 26                     shapes.Add(new Square() { Index = i });
 27                 }
 28                 else if (value < 10)
 29                 {
 30                     shapes.Add(new Triangle() { Index = i });
 31                 }
 32                 else
 33                 {
 34                     shapes.Add(new Circle() { Index = i });
 35                 }
 36             }
 37 
 38             shapes.Sort(
 39                 (left, right) =>
 40                 {
 41                     if (left < right)
 42                     {
 43                         return -1;
 44                     }
 45 
 46                     if (left > right)
 47                     {
 48                         return 1;
 49                     }
 50 
 51                     return 0;
 52                 });
 53             shapes.ForEach(shape => shape.Draw());
 54 
 55             Console.ReadLine();
 56         }
 57     }
 58     
 59     public class Shape
 60     {
 61         public int Index { get; set; }
 62 
 63         public virtual void Draw()
 64         {
 65             Console.WriteLine($"画了Shape基类{Index}");
 66         }
 67 
 68         public static bool operator <(Shape left, Shape right)
 69         {
 70             var leftTypeName = left.GetType().Name;
 71             var leftIndex = -1;
 72             var rightTypeName = right.GetType().Name;
 73             var rightIndex = -1;
 74             for (int i = 0; i < Program.OrderStrings.Length; i++)
 75             {
 76                 if (leftTypeName == Program.OrderStrings[i])
 77                 {
 78                     leftIndex = i;
 79                 }
 80 
 81                 if (rightTypeName == Program.OrderStrings[i])
 82                 {
 83                     rightIndex = i;
 84                 }
 85             }
 86             return leftIndex < rightIndex;
 87         }
 88 
 89         public static bool operator >(Shape left, Shape right)
 90         {
 91             return !(left < right);
 92         }
 93     }
 94 
 95     public class Square:Shape
 96     {
 97         public override void Draw()
 98         {
 99             Console.WriteLine($"画了正方形{Index}");
100         }
101     }
102 
103     public class Circle : Shape
104     {
105         public override void Draw()
106         {
107             Console.WriteLine($"画了圆{Index}");
108         }
109     }
110 
111     public class Triangle : Shape
112     {
113         public override void Draw()
114         {
115             Console.WriteLine($"画了三角形{Index}");
116         }
117     }
118 }