Join two object lists in CSharp

Description

The following code shows how to join two object lists.

Example


   /*from  w ww  .ja  v a 2  s . c  om*/
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 MyRole {
    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<MyRole> roles = new List<MyRole> {
              new MyRole  { ID = 1, Role = "Manager" },
              new MyRole  { 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 };
        foreach(var v in query){
            Console.WriteLine(v.FirstName);
        }
    }
}

The code above generates the following result.





















Home »
  C# Tutorial »
    LINQ »




Operator
Select
Where
OrderBy
Group
Join
Let
LINQ