Loopup集合类笔记

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;

namespace  Lookup
{
class  Program
{
static   void  Main( string [] args)
{
Person graham  =   new  Person( " Graham " ,  " Hill " ,  " USA " );
Person emerson  =   new  Person( " Emerson " ,  " Fittipaldi " ,  " USA " );
Person hc  =   new  Person( " Huang " ,  " Cong " ,  " CA " );
List < Person >  listPerson  =   new  List < Person > () { graham, emerson, hc };

Lookup < string , Person >  Persons  =  (Lookup < string , Person > )listPerson.ToLookup(r  =>  r.Counary);

foreach  (Person obj  in  Persons[ " USA " ])
{
Console.WriteLine(obj.FirstName  +   "   " +  obj.LastName);
}
}
}

public   class  Person
{
public   string  FirstName {  get ;  set ; }
public   string  LastName {  get ;  set ; }
public   string  Counary {  get ;  set ; }

public  Person( string  first,  string  last, string  counary)
{
FirstName  =  first;
LastName  =  last;
Counary  =  counary;
}
}
}