裝飾器模式動態地給一個對象添加一些額外的職責。就增加功能來說，裝飾器模式相比生成子類更為靈活。

// 組件接口  
public interface IComponent  
{  void Operation();  
}  // 具體組件  
public class ConcreteComponent : IComponent  
{  public void Operation()  {  Console.WriteLine("ConcreteComponent.Operation()");  }  
}  // 裝飾器抽象類  
public abstract class Decorator : IComponent  
{  protected IComponent _component;  public Decorator(IComponent component)  {  _component = component;  }  public virtual void Operation()  {  _component.Operation();  }  
}  // 具體裝飾器  
public class ConcreteDecoratorA : Decorator  
{  public ConcreteDecoratorA(IComponent component) : base(component) {}  public override void Operation()  {  base.Operation();  AddedFunctionality();  }  private void AddedFunctionality()  {  Console.WriteLine("Added functionality in ConcreteDecoratorA");  }  
}  // 客戶端代碼  
class Program  
{  static void Main(string[] args)  {  IComponent component = new ConcreteComponent();  // 裝飾者模式的使用  component = new ConcreteDecoratorA(component);  // 執行操作  component.Operation();  }  
}