1. 投影操作符—【LINQ標準查詢操作符】

public class Select_LINQ    {        public static  string ContextString = System.Configuration.ConfigurationSettings.AppSettings["ContextString"].ToString();        public static void Print()        {            DataContext context = new DataContext(ContextString);            Table<Contact> contact = context.GetTable<Contact>();            var querySyntex = from c in contact                        where c.FirstName.StartsWith("S")                        select new { c.FirstName, c.LastName, c.EmailAddress };            var methodSyntex = contact.Select(c => new { c.FirstName, c.LastName, c.EmailAddress }).Where(con => con.FirstName.StartsWith("S"));            Console.WriteLine("============== Query Syntex ==============");            foreach (var item in querySyntex.Take(10))            {                                Console.WriteLine(item.ToString());            }            Console.WriteLine("\n");            Console.WriteLine("============== Method Syntex ==============");            foreach (var item in methodSyntex.Take(10))            {                                Console.WriteLine(item.ToString());            }            Console.ReadKey();        }    }    public class SelectMany_LINQ    {        public static void Print()        {            Names[] names = {               new Names{FirstName = "J. Phillip",Pets = new List<string>{"Yudon","Fido"}},              new Names{FirstName = "Michelle",Pets = new List<string>{"Alexander","Alcorn"}},              new Names{FirstName = "Maxwell",Pets = new List<string>{"Alpuerto","Arakawa"}} };            IEnumerable<string> nameQuery = names.AsQueryable().SelectMany(n => n.Pets);                        //List<string> list = nameQuery.ToList<string>();// 立即執行            foreach (var item in nameQuery)            {                Console.WriteLine(item);            }            Console.WriteLine("\n");            // 注意nameQuery 與 nameQuery2 的區別            /*             * IEnumerable介面提供了向前遍曆的功能，它不具有在各個資料項目之間移動（向前移動除外）的能力             * 然而，IQueryable可以可以使查詢操作更具靈活性，雖然是IQueryable實現了IEnumerable，但IEnumerable             * 為IQueryable提供了遍曆功能。             */            IQueryable nameQuery2 = names.AsQueryable().Select(n => n);            foreach (var item in nameQuery2)            {                Console.WriteLine(((Names)item).FirstName);                foreach (var p in ((Names)item).Pets)                {                    Console.WriteLine(" " + p.ToString());                }                            }            Console.ReadKey();        }    }    struct Names    {      public string FirstName;             public List<string> Pets;    }