[再读书]索引器

     class  Person
    {
         private   string  strName  =   string .Empty;

         public  Person( string  strName)
        {
             this .strName  =  strName;
        }

         public   string  StrName
        {
             get
            {
                 return  strName;
            }
        }
    }

     ///   <summary>
     ///  Person容器
     ///   </summary>
     class  foo
    {
        List < Person >  persons  =   new  List < Person > ();

         ///   <summary>
         ///  索引器
         ///   </summary>
         ///   <param name="index"></param>
         ///   <returns></returns>
         public  Person  this [ int  index]
        {
             get
            {
                 return  persons[index];
            }
             set
            {
                persons[index]  =  value;
            }
        }

         ///   <summary>
         ///  重载索引器
         ///   </summary>
         ///   <param name="strName"></param>
         ///   <returns></returns>
         public  Person  this [ string  strName]
        {
             get
            {
                 foreach  (Person pr  in  persons)
                {
                     if  (pr.StrName  ==  strName)
                    {
                         return  pr;
                    }
                }
                 return  persons[ 0 ];
            }
        }

         ///   <summary>
         ///  添加
         ///   </summary>
         ///   <param name="person"> Person实例 </param>
         public   void  AddPerson(Person person)
        {
            persons.Add(person);
        }

         ///   <summary>
         ///  移除
         ///   </summary>
         ///   <param name="person"></param>
         public   void  RemovePerson(Person person)
        {
            persons.Remove(person);
        }

         ///   <summary>
         ///  计数器
         ///   </summary>
         public   int  Count
        {
             get
            {
                 return  persons.Count;
            }
        }
    }