策略模式

定义

 public interface ITraffic
 {
      void Drive();
  }

  public class Car:ITraffic
  {

      public void Drive()
      {
          Console.WriteLine("车在陆地行驶");
      }

  }

  public class Ship : ITraffic
  {
      public void Drive()
      {
          Console.WriteLine("船在水上行驶");
      }
  }

  public class AirPlane : ITraffic
  {

      public void Drive()
      {
          Console.WriteLine("飞机在天上飞");
      }
  }

  public class ErrorTraffic:ITraffic
  {
      public void Drive()
      {
          Console.WriteLine("选择错误");
      }
  }

  public class SelectTraffic
  {
      public readonly ITraffic _trafficType;
      public SelectTraffic(ITraffic traffic)
      {
          _trafficType = traffic;
      }

      public void Drive()
      {
          _trafficType.Drive();
      }
  }

调用

 Console.WriteLine("策略模式");
 SelectTraffic traffic = new SelectTraffic(new Car());
 traffic.Drive();
 traffic = new SelectTraffic(new Ship());
 traffic.Drive();
 traffic = new SelectTraffic(new AirPlane());
 traffic.Drive();