C#设计模式_创建型_FactoryMethod模式(learn from Lijianzhong & others)

意图：定义一个用于创建对象的接口，让子类决定实例化哪一个类。Factory Method 使一个类的实例化延迟到其子类。
适用性：

• 当一个类不知道它所必须创建的对象的类的时候。
• 当一个类希望由它的子类来指定它所创建的对象的时候。
• 当类将创建对象的职责委托给多个帮助子类中的某一个，并且你希望将哪一个帮助子类是代理者这一信息局部化的时候。

结构：

using System;

namespace DesignPattern
{
 /// <summary>
 /// FactoryMethod 的摘要说明。
 /// </summary>
 public abstract class AbstractCar
 {
  public abstract void Start();
  public abstract void Run();
  public abstract void Turn(Direction direction);
  public abstract void Stop();
 }
 public class CarTestFramework
 {
  public void BuildTestContext(CarFactory carFactory)
  {
   AbstractCar c1 = carFactory.CreateCar();
   AbstractCar c2 = carFactory.CreateCar();
   AbstractCar c3 = carFactory.CreateCar();
   AbstractCar c4 = carFactory.CreateCar();
  
  }
  public void DoTest(AbstractCar car)
  {
   car.Run();
  }
  public TestData GetTestData()
  {
  
  }
 }
 public abstract class CarFactory{
  public abstract Car CreateCar();
  
 }
 public class HongqiCar: AbstractCar{
  Engine engin1;
  Engine engin2;
  Engine engin3;
  Engine engin4;
  public override void Start(){}
  public override void Run(){}
  public override void Turn(Direction direction){}
  public override void Stop(){}
 }
 public class DongfengCar : AbstractCar{
  Engine engin1;
  Engine engin2;
  public override void Start(){}
  public override void Run(){}
  public override void Turn(Direction direction){}
  public override void Stop(){}
 }
 public class HongqiCarFactory : CarFactory
 {
  public override AbstractCar CreateCar()
  {
   return new HongqiCar();
  }

 }
 public class DongfengCarFactory : CarFactory
 {
  public override AbstractCar CreateCar()
  {
   return new DongfengCar();
  }
 }

 class App
 {
  public static void Main(){   
   CarTestFramework carTestFamework = new CarTestFramework();
   carTestFamework.BuildTestContext(new HongqiCarFactory());
   CarTestFramework carTestFamework = new CarTestFramework();
   carTestFamework.BuildTestContext(new DongfengCarFactory());

   //Activator.CreateInstance(string TypeName)
  }
 }

 public class FactoryMethod
 {
  public FactoryMethod()
  {
   //
   // TODO: 在此处添加构造函数逻辑
   //
  }
  
 }
}