索引器

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            //通过索引取值
            Person p = new Person();
            p[1] = "tom";
            Console.WriteLine(p[1] + p[2]);
            //p["sum", 9, 8] = "bbb";//错误，不能设置值
            Console.WriteLine(p["jim", 9, 8]);//只读
            Console.ReadKey();
        }
        class Person
        {
            private string FirstName = "张三";
            private string SecondName = "李四";
            public string this[int index]
            {
                get { 
                    if(index==1)
                    {
                        return FirstName;
                    }
                    else if (index == 2)
                    {
                        return SecondName;
                    }
                    else
                    {
                        throw new Exception("数据异常");
                    }
                }
                set { 
                    if(index==1)
                    {
                        FirstName = value;
                    }
                    else if (index == 2)
                    {
                        SecondName = value;
                    }
                    else
                    {
                        throw new Exception("数据异常");
                    }
                }
            }
            private string Name = "aaa";
            private int x = 1;
            private int y = 2;
            public string this[string name, int x, int y]//可以重载
            {
                get {
                    return Name + x + y;
                }
            }
        }
    }
}