Linq小例子

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Test t1 = new Test { ID = 23, Age = 23, Name = "测试" };
            rtbx.AppendText(t1+"/r/n");

            //直接输入类别，隐匿调用t1的ToString()方法。
            List list = new List
            {
                new Test{ID=1,Age=10,Name="One"},
                new Test(){ID=2,Age=20,Name="Two"},
                new Test(){ID=3,Age=30,Name="Three"},
                new Test(){ID=4,Age=40,Name="Four"}
            };
            //var items = from t in list
            //            where t.Age > 15
            //            orderby t.ID descending
            //            select new{编号=t.ID,姓名=t.Name,年龄=t.Age};

 

            var items = list.Where(n => n.Age > 15).OrderByDescending(x => x.ID).Select(y => new { 编号 = y.ID, 姓名 = y.Name, 年龄 = y.Age });

 

         //在查询语法中需要select子句，但在以前并没有看到Select()方法，因为在LINQ方法语法中不需要它，除非在进行投射(改变结果集中所查询的原始类型)。

            foreach (var i in items)
            {
                rtbx.AppendText(i+"/r/n");
            }
       }
    }

    public class Test
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }

        public override string ToString()
        {
            return "ID:" + ID + " Name:" + Name + " Age:" + Age;
        }
    }