/// 
    /// 组合设计模式的基类。    /// 
    abstract class BaseElement    {        public abstract void Add(BaseElement e) { }        public abstract void Remove(BaseElement e) { }        public abstract void Duty() { }    }    /// 
    /// 字符    /// 
    public class CharElement:BaseElement    {        public override void Add(BaseElement e)        {            throw new NotImplementedException();        }        public override void Remove(BaseElement e)        {            throw new NotImplementedException();        }        public override void Duty()        {            Console.WriteLine("i am a char");        }    }    /// 
    /// 图片    /// 
    public class GraphicElement:BaseElement    {        public override void Add(BaseElement e)        {            throw new NotImplementedException();        }        public override void Remove(BaseElement e)        {            throw new NotImplementedException();        }        public override void Duty()        {            throw new NotImplementedException();        }    }    /// 
    /// 段落，一个段落有字符和图片组合而成    /// 
    public class ParagraphyElement:BaseElement    {        List
     
       children = new List
      
       ();        public override void Add(BaseElement e)        {            children.Add(e);        }        public override void Remove(BaseElement e)        {            children.Remove(e);        }        public override void Duty()        {            foreach (var item in children)            {                item.Duty();            }        }    }
      
     

 

组合设计模式