LINQ (C#)

背景

一直没搞懂LINQ里面的from、where、select那些，感觉像是SQL查询语句

学习过程

示例代码：

  class Program
    {
        public class Custom
        {
            public string City { get; set; }
            public string FirstName { get; set; }
            public string LastName { get; set; }
            public string Address { get; set; }

        }
        static void Main(string[] args)
        {
            List<Custom> Customers = new List<Custom>
            {
                 new Custom { City = "beijing",FirstName="li",LastName="p",Address="bj"  },
                 new Custom { City = "shanghai", FirstName="sun",LastName="m",Address="sh"},
                 new Custom { City = "shenzhen",FirstName="wang",LastName="y",Address="sz" }
             };
            var result1 = from c in Customers
                          where c.City.StartsWith("s")
                          orderby c.LastName
                          select new { c.FirstName, c.LastName, c.Address };

            //与上方代码是等效的
            //var result2 = Customers.Where(c => c.City.StartsWith("s"))
            //           .OrderBy(c => c.LastName)
            //           .Select(c => new { c.FirstName, c.LastName, c.Address });
            foreach (var item in result1)
            {
                Console.WriteLine(item.Address);
            }
            //output
            //sh
            //sz
            Console.ReadKey();
        }
    }

参考网址

Understanding LINQ (C#)