索引函数的使用二

//程序清单P7_4.cs:
using System;

namespace P7_4
{
    public class IndexerSample
    {
        public static void Main()
        {
            Person p1 = new Person("李明");
            p1["BusinessPhone"] = "01060010800";
            p1["BUSINESSFax"] = "01060010801";
            p1["mobilephone"] = "13310061006";
            p1.Output();
        }
    }

    public class Person
    {
        //字段
        private string m_name;
        private string m_busiPhone;
        private string m_busiFax;
        private string m_homePhone;
        private string m_mobilePhone;

        //属性
        public string Name
        {
            get
            {
                return m_name;
            }
            set
            {
                m_name = value;
            }
        }

        //索引函数
        public string this[string sType]
        {
            get
            {
                string type = sType.ToUpper();
                switch (type)
                {
                    case "BUSINESSPHONE":
                        return m_busiPhone;
                    case "BUSINESSFAX":
                        return m_busiFax;
                    case "HOMEPHONE":
                        return m_homePhone;
                    case "MOBILEPHONE":
                        return m_mobilePhone;
                    default:
                        return null;
                }
            }
            set
            {
                string type = sType.ToUpper();
                switch (type)
                {
                    case "BUSINESSPHONE":
                        m_busiPhone = value;
                        break;
                    case "BUSINESSFAX":
                        m_busiFax = value;
                        break;
                    case "HOMEPHONE":
                        m_homePhone = value;
                        break;
                    case "MOBILEPHONE":
                        m_mobilePhone = value;
                        break;
                    default:
                        throw new ArgumentOutOfRangeException();
                }
            }
        }

        //构造函数
        public Person()
        {
        }

        public Person(string sName)
        {
            m_name = sName;
        }

        //方法
        public void Output()
        {
            Console.WriteLine(m_name);
            Console.WriteLine("商务电话: {0}", m_busiPhone);
            Console.WriteLine("商务传真: {0}", m_busiFax);
            Console.WriteLine("家庭电话: {0}", m_homePhone);
            Console.WriteLine("移动电话: {0}", m_mobilePhone);
        }
    }
}