в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:18:13Z

1 версия

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==Cartesian Join demo==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class MainClass
{
static void Main()
{
var query = from first in Enumerable.Range(1, 5)
from second in Enumerable.Range(1, first)
select new { first, second };
foreach (var item in query)
{
Console.WriteLine(item);
}
}
}</source>

==Join Operator==

<source lang="csharp">using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

public class Employee {
public int id;
public string firstName;
public string lastName;
public static ArrayList GetEmployeesArrayList() {
ArrayList al = new ArrayList();
al.Add(new Employee { id = 1, firstName = "J", lastName = "R" });
al.Add(new Employee { id = 2, firstName = "W", lastName = "G" });
al.Add(new Employee { id = 3, firstName = "A", lastName = "H" });
al.Add(new Employee { id = 4, firstName = "D", lastName = "L" });
al.Add(new Employee { id = 101, firstName = "K", lastName = "F" });
return (al);
}
public static Employee[] GetEmployeesArray() {
return ((Employee[])GetEmployeesArrayList().ToArray());
}
}
public class EmployeeOptionEntry {
public int id;
public long optionsCount;
public DateTime dateAwarded;
public static EmployeeOptionEntry[] GetEmployeeOptionEntries() {
EmployeeOptionEntry[] empOptions = new EmployeeOptionEntry[] {
new EmployeeOptionEntry {
id = 1,
optionsCount = 2,
dateAwarded = DateTime.Parse("1999/12/31") },
new EmployeeOptionEntry {
id = 101,
optionsCount = 2,
dateAwarded = DateTime.Parse("1998/12/31") }
};
return (empOptions);
}
}
public class MainClass {
public static void Main() {
Employee[] employees = Employee.GetEmployeesArray();
EmployeeOptionEntry[] empOptions = EmployeeOptionEntry.GetEmployeeOptionEntries();
var employeeOptions = employees
.Join(
empOptions,
e => e.id,
o => o.id,
(e, o) => new
{
id = e.id,
name = string.Format("{0} {1}", e.firstName, e.lastName),
options = o.optionsCount
});
foreach (var item in employeeOptions)
Console.WriteLine(item);
}
}</source>

==Join three object list==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;
class Salary {
int _id;
int _year;
double _salary;
public int ID {
get { return _id; }
set { _id = value; }
}
public int Year {
get { return _year; }
set { _year = value; }
}
public double SalaryPaid {
get { return _salary; }
set { _salary = value; }
}
}
class Employee {
int _id;
int _idRole;
string _lastName;
string _firstName;
public int ID {
get { return _id; }
set { _id = value; }
}
public int IDRole {
get { return _idRole; }
set { _idRole = value; }
}
public string LastName {
get { return _lastName; }
set { _lastName = value; }
}
public string FirstName {
get { return _firstName; }
set { _firstName = value; }
}
}
class Role {
int _id;
string role;
public int ID {
get { return _id; }
set { _id = value; }
}
public string Role {
get { return role; }
set { role = value; }
}
}
public class MainClass {
public static void Main() {
List<Employee> people = new List<Employee> {
new Employee { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
new Employee { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
new Employee { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
new Employee { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
};
List<Role> roles = new List<Role> {
new Role { ID = 1, Role = "Manager" },
new Role { ID = 2, Role = "Developer" }
};
List<Salary> salaries = new List<Salary> {
new Salary { ID = 1, Year = 2004, SalaryPaid = 10.00 },
new Salary { ID = 1, Year = 2005, SalaryPaid = 15.00 },
new Salary { ID = 1, Year = 2005, SalaryPaid = 15.00 }
};
var query = from p in people
join s in salaries on p.ID equals s.ID
select new { p.FirstName, p.LastName, s.SalaryPaid };
var querySum = from q in query
group q by q.LastName into gp
select new { LastName = gp.Key, TotalSalary = gp.Sum(q => q.SalaryPaid) };
}
}</source>

==Join two object lists==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;
class Person {
int _id;
int _idRole;
string _lastName;
string _firstName;
public int ID {
get { return _id; }
set { _id = value; }
}
public int IDRole {
get { return _idRole; }
set { _idRole = value; }
}
public string LastName {
get { return _lastName; }
set { _lastName = value; }
}
public string FirstName {
get { return _firstName; }
set { _firstName = value; }
}
}
class Role {
int _id;
string role;
public int ID {
get { return _id; }
set { _id = value; }
}
public string Role {
get { return role; }
set { role = value; }
}
}
class Program {
static void Main(string[] args) {
List<Person> people = new List<Person> {
new Person { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
new Person { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
new Person { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
new Person { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
};
List<Role> roles = new List<Role> {
new Role { ID = 1, Role = "Manager" },
new Role { ID = 2, Role = "Developer" }
};
var query = from p in people
where p.ID == 1
from r in roles
where r.ID == p.IDRole
select new { p.FirstName, p.LastName, r.Role };
}
}</source>

==Use join key word==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;
class Person {
int _id;
int _idRole;
string _lastName;
string _firstName;
public int ID {
get { return _id; }
set { _id = value; }
}
public int IDRole {
get { return _idRole; }
set { _idRole = value; }
}
public string LastName {
get { return _lastName; }
set { _lastName = value; }
}
public string FirstName {
get { return _firstName; }
set { _firstName = value; }
}
}
class Role {
int _id;
string role;
public int ID {
get { return _id; }
set { _id = value; }
}
public string Role {
get { return role; }
set { role = value; }
}
}
class Program {
static void Main(string[] args) {
List<Person> people = new List<Person> {
new Person { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
new Person { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
new Person { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
new Person { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
};
List<Role> roles = new List<Role> {
new Role { ID = 1, Role = "Manager" },
new Role { ID = 2, Role = "Developer" }
};
var query = from p in people
join r in roles on p.IDRole equals r.ID
select p;
}
}</source>

==Use Join on==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;
class Salary {
int _id;
int _year;
double _salary;
public int ID {
get { return _id; }
set { _id = value; }
}
public int Year {
get { return _year; }
set { _year = value; }
}
public double SalaryPaid {
get { return _salary; }
set { _salary = value; }
}
}
class Employee {
int _id;
int _idRole;
string _lastName;
string _firstName;
public int ID {
get { return _id; }
set { _id = value; }
}
public int IDRole {
get { return _idRole; }
set { _idRole = value; }
}
public string LastName {
get { return _lastName; }
set { _lastName = value; }
}
public string FirstName {
get { return _firstName; }
set { _firstName = value; }
}
}
class Role {
int _id;
string role;
public int ID {
get { return _id; }
set { _id = value; }
}
public string Role {
get { return role; }
set { role = value; }
}
}
public class MainClass {
public static void Main() {
List<Employee> people = new List<Employee> {
new Employee { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
new Employee { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
new Employee { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
new Employee { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
};
List<Role> roles = new List<Role> {
new Role { ID = 1, Role = "Manager" },
new Role { ID = 2, Role = "Developer" }
};
List<Salary> salaries = new List<Salary> {
new Salary { ID = 1, Year = 2004, SalaryPaid = 10000.00 },
new Salary { ID = 1, Year = 2005, SalaryPaid = 15000.00 },
new Salary { ID = 1, Year = 2005, SalaryPaid = 15000.00 }
};
var query = from p in people
join s in salaries on p.ID equals s.ID
where p.ID == 1
select s.SalaryPaid;
Console.Write(query.Min());
Console.Write(query.Max());
}
}</source>

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Csharp/CSharp Tutorial/LINQ/Join - История изменений

в 15:31, 26 мая 2010

Admin: 1 версия