C# 设计模式系列教程-简单工厂模式

 /// <summary>
 /// 简单工厂类，用sealed修饰，
 /// </summary>
 public class SimpleProductFactory
 {
  /// <summary>
  /// 使用静态方法，根据传入的参数来指定要实例化哪一种产品
  /// </summary>
  /// <param name="productType"></param>
  /// <returns></returns>
  public static Product CreateProduct(string productType)
  {
   Product product = null;
   switch (productType)
   {
    case "A":
     product = new ConcreteProductA();
     break;
    case "B":
     product = new ConcreteProductB();
     break;
   }

   return product;
  }
 }

 /// <summary>
 /// 抽象产品
 /// </summary>
 public abstract class Product
 {
  public Product()
  { }

  public abstract void Opration();
 }

 /// <summary>
 /// 具体产品 A
 /// </summary>
 public class ConcreteProductA : Product
 {
  public ConcreteProductA() { }

  public override void Opration()
  {
   // 产品A
  }
 }

 /// <summary>
 /// 具体产品 B
 /// </summary>
 public class ConcreteProductB : Product
 {
  public ConcreteProductB() { }

  public override void Opration()
  {
   //产品B
  }
 }