详解C#的设计模式编程之抽象工厂模式的应用

  #region 炸弹系列
  abstract class Bomb
  {
    abstract public void baozha();
  }
  /// <summary>
  /// 导弹
  /// </summary>
  class daodanBomb :Bomb
  {
    public override void baozha()
    {
      Console.WriteLine("我是一颗中国造导弹，来轰炸不老实的小邪恶国家！");
    }
  }
  /// <summary>
  /// 核弹
  /// </summary>
  class hedanBomb : Bomb
  {
    public override void baozha()
    {
      Console.WriteLine("我是一颗中国造核弹，来轰炸不老实的小邪恶国家！");
    }
  }
  #endregion

  #region 坦克系列
  abstract class Tank
  {
    abstract public void go();
  }
  /// <summary>
  /// 越野车
  /// </summary>
  class yueyeTank : Tank
  {
    public override void go()
    {
      Console.WriteLine("我是一颗中国造越野车，来踏平不老实的小邪恶国家！");
    }
  }
  /// <summary>
  /// 主站坦克
  /// </summary>
  class zhuzhanTank : Tank
  {
    public override void go()
    {
      Console.WriteLine("我是一颗中国造主站坦克，来踏平不老实的小邪恶国家！");
    }
  }
  #endregion工厂类代码


  #region 中国兵工厂
  abstract class chinaFactory
  {
    //装甲车制造车间
    public abstract Tank CreateTank();
    //炸弹知道车间
    public abstract Bomb CreateBomb();
  }
  //兵工厂前期制造
  class qianqiFactory : chinaFactory
  {   
    public override Bomb CreateBomb()
    {
      //导弹
      return new daodanBomb();
    }
    public override Tank CreateTank()
    {
      //越野车
      return new yueyeTank();
    }
  }
  //兵工厂后期制造
  class houqiFactory : chinaFactory
  {
    public override Bomb CreateBomb()
    {
      //核弹
      return new hedanBomb();
    }
    public override Tank CreateTank()
    {
      //主站坦克
      return new zhuzhanTank();
    }
  }
  #endregion客户端代码：（打仗）


  // 备战
  class Make
  {
    //装备 
    private Bomb bomb;
    private Tank tank;
    //制造加工
    public Make(chinaFactory factory)
    {
      bomb = factory.CreateBomb();
      tank = factory.CreateTank();
    }

    //开始打仗
    public void warStar()
    {
      //炸弹类爆炸
      bomb.baozha();
      //战车类前进
      tank.go();
    }

  }
  public class start
  {
    public static void Main()
    {
      //大战前期
      chinaFactory qianqiMake = new qianqiFactory();
      Make qianqi = new Make(qianqiMake);
      qianqi.warStar();

      //点任意键，进行后期攻势！！
      Console.ReadKey();

      //大战后期
      chinaFactory houqiMake = new houqiFactory();
      Make houqi = new Make(houqiMake);
      houqi.warStar();

      Console.WriteLine("钓鱼岛是中国的，神圣不可侵犯！小邪恶国家，滚开！！");
      Console.ReadLine();
    }
  }

/// 扮演抽象工厂的角色
/// 创建连接数据库时所需要的对象集合，
/// 这个对象集合包括有 DbConnection对象（这个是抽象产品类,如绝味例子中的YaBo类）、DbCommand类、DbDataAdapter类，针对不同的具体工厂都需要实现该抽象类中方法，
public abstract class DbProviderFactory
{
  // 提供了创建具体产品的接口方法
  protected DbProviderFactory();
  public virtual DbCommand CreateCommand();
  public virtual DbCommandBuilder CreateCommandBuilder();
  public virtual DbConnection CreateConnection();
  public virtual DbConnectionStringBuilder CreateConnectionStringBuilder();
  public virtual DbDataAdapter CreateDataAdapter();
  public virtual DbDataSourceEnumerator CreateDataSourceEnumerator();
  public virtual DbParameter CreateParameter();
  public virtual CodeAccessPermission CreatePermission(PermissionState state);
}
DbProviderFactory类是一个抽象工厂类，该类提供了创建数据库连接时所需要的对象集合的接口，实际创建的工作在其子类工厂中进行，微软使用的是SQL Server数据库，因此提供了连接SQL Server数据的具体工厂实现，具体代码可以用反编译工具查看，具体代码如下：

/// 扮演着具体工厂的角色，用来创建连接SQL Server数据所需要的对象
public sealed class SqlClientFactory : DbProviderFactory, IServiceProvider
{
  // Fields
  public static readonly SqlClientFactory Instance = new SqlClientFactory();
  // 构造函数
  private SqlClientFactory()
  {
  }
      
  // 重写抽象工厂中的方法
  public override DbCommand CreateCommand()
  { // 创建具体产品
    return new SqlCommand();
  }
  public override DbCommandBuilder CreateCommandBuilder()
  {
    return new SqlCommandBuilder();
  }
  public override DbConnection CreateConnection()
  {
    return new SqlConnection();
  }
  public override DbConnectionStringBuilder CreateConnectionStringBuilder()
  {
    return new SqlConnectionStringBuilder();
  }
  public override DbDataAdapter CreateDataAdapter()
  {
    return new SqlDataAdapter();
  }
  public override DbDataSourceEnumerator CreateDataSourceEnumerator()
  {
    return SqlDataSourceEnumerator.Instance;
  }
  public override DbParameter CreateParameter()
  {
    return new SqlParameter();
  }
  public override CodeAccessPermission CreatePermission(PermissionState state)
  {
    return new SqlClientPermission(state);
  }
}