SelectMany等LINQ运算符的使用

 public class Racer : IComparable<Racer>, IFormattable
     {
         public string FirstName { get; set; }
         public string LastName { get; set; }
         public int Wins { get; set; }
         public string Country { get; set; }
         public int Starts { get; set; }
         public IEnumerable<string> Cars { get; set; }
         public IEnumerable<int> Years { get; set; }

         public Racer(string firstName,string lastName,string country,int wins,int starts,IEnumerable<int> years,IEnumerable<string> cars)
         {
             FirstName = firstName;
             LastName = lastName;
             Wins = wins;
             Country = country;
             Starts = starts;
             Cars = new List<string>(cars);
             Years = new List<int>(years);
         }

         public Racer(string firstName, string lastName, int wins, string country, int starts)
             : this(firstName, lastName,country, wins, starts,null, null)
         {

         }

         public override string ToString()
         {
             return string.Format("{0}_{1}", FirstName, LastName);
         }

         public int CompareTo(Racer other)
         {
             if (other == null) return -;
             int result = string.Compare(FirstName, other.FirstName);
             if (result == )
                 result = string.Compare(LastName, other.LastName);
             return result;
         }

         public string ToString(string format, IFormatProvider formatProvider)
         {
             format = format ?? "N";
             switch(format)
             {
                 case "N":
                     return ToString();
                 case "C":
                     return string.Format("{0} Country:{1}", ToString(), Country);
                 case "S":
                     return string.Format("{0} Starts:{1}", ToString(), Starts);
                 case "W":
                     return string.Format("{0} Wins:{1}", ToString(), Wins);
                 case "Y":
                     var result=ToString();
                     foreach(var item in Years)
                     {
                         result += item;
                     }
                     return result;
                 default:
                     throw new FormatException(string.Format("Format {0} not supported", format));
             }
         }
     }

 public class Team
     {
         public string Name { get; private set; }
         public IEnumerable<int> Years { get; private set; }

         public Team(string name,params int[] years)
         {
             Name = name;
             Years = new List<int>(years);
         }
     }

 public static class Formula1
     {
         private static List<Racer> racers;
         private static List<Team> teams;

         public static List<Racer> Racers
         {
             get { return racers ?? (racers = new List<Racer>() { new Racer("Nino", "Farina", "Italy", , , new[] {  }, new[] { "Alfa Romeo" }), new Racer("Alberto", "Ascari", "Italy", , , new[] { ,  }, new[] { "Ferrari" }), new Racer("Juan Manuel", "Fangio", "Argentina", , , new[] { , , , ,  }, new[] { "Alfa Romeo", "Maserati" }), new Racer("Mike", "Hawthorn", "UK", , , new[] {  }, new[] { "Ferrari" }) }); }
         }

         public static List<Team> Teams
         {
             get
             {
                 return teams ?? (teams = new List<Team>{new Team("Vanwall",),
                     new Team("Cooper", , ),
                     new Team("Ferrari", , , , , , , ,, , , , , , , , ),
                     new Team("BRM", ),
                     new Team("Lotus", , , , , , , ),
                     new Team("Brabham", , ),
                     new Team("Matra", ),
                     new Team("Tyrrell", )});
             }
         }
     }

 static void Main(string[] args)
         {
             var result = from r in Formula1.Racers
                          from c in r.Cars
                          where c.Equals("Ferrari")
                          orderby r.FirstName
                          select r.FirstName + " " + r.LastName;

             foreach(var item in result)
             {
                 Console.WriteLine(item);
             }

             var result2 = Formula1.Racers.SelectMany(r => r.Cars, (r, c) => new { Racer = r, Car = c })
                 .Where(r => r.Car.Equals("Ferrari")).OrderBy(r => r.Racer.FirstName).Select(r => r.Racer.FirstName + " " + r.Racer.LastName);

             Console.ReadKey();
         }