LINQ学习笔记

 int[] numbers = new int[] { 10, 55, 43, 13, 57, 40, 22, 88 };

var result =
                from number in numbers
                where number % 2 == 0
                orderby number descending
                select number;

            foreach (var item in result)
            {
                Console.Write("{0}\t", item);
            }

------------------------------------------------------------------------

string[] words = { "hello", "wonderful", "linq", "beautiful", "world" };

            var groups =
                from word in words
                orderby word ascending
                group word by word.Length into lengthGroup
                orderby lengthGroup.Key descending
                select new { Length = lengthGroup.Key, Words = lengthGroup };

            foreach (var group in groups)
            {
                Console.WriteLine("Words of length " + group.Length);
                foreach (string word in group.Words)
                    Console.WriteLine(" " + word);
            }

------------------------------------------------------------------------

string[] words = { "hello", "wonderful", "linq", "beautiful", "world" };

            var shortWords =
                from word in words
                where word.Length <= 5
                select word;

            foreach (var word in shortWords)
                Console.WriteLine(word);

------------------------------------------------------------------------

DataContext dataContext = new DataContext(@"Data Source=......");
            Table<T_IC_APP> appsTable = dataContext.GetTable<T_IC_APP>();

            var apps =
                from app in appsTable
                where app.APP_NAME.Contains("FF")
                select app;

            Console.WriteLine(dataContext.GetCommand(apps).CommandText);

            foreach (var item in apps)
            {
                Console.WriteLine("APP_ID: {0}, APP_NAME: {1}, APP_DESC: {2}",
                    item.APP_ID, item.APP_NAME, item.APP_DESC);
            }

[Table(Name = "T_IC_APP")]
        public class T_IC_APP
        {
            [Column(IsPrimaryKey = true, Name = "APP_ID")]
            public string APP_ID { get; set; }

            [Column(Name = "APP_NAME")]
            public string APP_NAME { get; set; }

            [Column(Name = "APP_DESC")]
            public string APP_DESC { get; set; }
        }

------------------------------------------------------------------------

 Book[] books = new Book[]
            {
                new Book("Ajax in Action", "Manning", 2005),
                new Book("Windows Forms in Action", "Manning", 2006),
                new Book("RSS and Atom in Action", "Manning", 2006)
            };

            XElement xml = new XElement("books",
                from book in books
                where book.Year == 2006
                select new XElement("book",
                    new XAttribute("title", book.Title),
                    new XElement("publisher", book.Publisher)
                    )
            );

            Console.WriteLine(xml);
        }

    class Book
    {
        public string Publisher;
        public string Title;
        public int Year;

        public Book(string title, string publisher, int year)
        {
            Title = title;
            Publisher = publisher;
            Year = year;
        }
    }