C # LINQ and LAMDA expression application experience GroupBy grouping

Example 1:

Application of GroupBy grouping in list<> generics

Original table:

Results by name Nam Group:

Lamda queries on a DataTable must be added in a reference to the project System.Data.DataSetExtensions

Code:

    Public partial class Form1:form {public Form1 () {InitializeComponent ();                } list<person> persons1 = new list<person> ();          private void Form1_Load (object sender, EventArgs e) {initform (); } private void InitForm () {//form initialize PERSONS1.              ADD (New person ("Zhang San", "male", 20, 1500)); Persons1.              ADD (New person ("Wang Cheng", "male", 32, 3200)); Persons1.              ADD (New person ("Lily", "female", 19, 1700)); Persons1.              ADD (New person ("joint", "female", 35, 3600)); Persons1.              ADD (New person ("joint", "female", 18, 1600));                Datagridview1.datasource = persons1; } private void Button1_Click (object sender, EventArgs e) {//******* pairs the collection by name belongs to group GR              Oupby query The fields included in the ********//results://1, grouped keywords: Name = g.key//2, number of each group: Count = G.count () 3, each group ofTotal Age: Agec = g.sum (item + item. Age)//4, sum of revenue per grouping: MONEYC = g.sum (item + Item). Money)//notation 1:lamda expression (recommended) var ls = persons1. GroupBy (A = a.name). Select (g = (New {name = G.key, Count = G.count (), AGEC = g.sum (item + Item). Age), MONEYC = g.sum (item = Item.              (Money)})); Notation 2: Class SQL language The final compiler translates it into LAMDA expression var ls2 = from PS in PERSONS1 Group PS by PS. Name into G select New {name = G.key, Count = G.count (), Agec = G.sum (item = Item.) Age), MONEYC = g.sum (item = Item.                    Money)}; Datagridview1.datasource = ls.             ToList (); Datagridview1.datasource = LS2.          ToList (); }}///<summary>///Manually design a person class.          Used to place the list generic in////</summary> public class Person {public string Name {get; set;}          public int Age {get;private set;}public string Sex {get; set;}                public int Money {get; set;}              Public person (string name, string sex, int. int, int money) {name = name;              Age = age;              sex = sex;          Money = money;   }      }

C # LINQ and LAMDA expression application experience GroupBy grouping