в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:18:07Z

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==Projection Creates New Objects==

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

class Customer
{
public string ID { get; set; }
public string City { get; set; }
public string Country { get; set; }
public string Region { get; set; }
public decimal Sales { get; set; }
public override string ToString()
{
return "ID: " + ID + " City: " + City + " Country: " + Country + " Region: " + Region + " Sales: " + Sales;
}
}
class Program
{
static void Main(string[] args)
{
List<Customer> customers = new List<Customer> {
new Customer { ID="A", City="New York", Country="USA", Region="North America", Sales=9999},
new Customer { ID="R", City="Beijing", Country="China", Region="Asia", Sales=9000 },
new Customer { ID="T", City="Lima", Country="Peru", Region="South America", Sales=2002 }
};
var queryResults =
from c in customers
where c.Region == "Asia"
select new { c.City, c.Country, c.Sales }
;
foreach (var item in queryResults)
{
Console.WriteLine(item);
}
}
}</source>

==Projection Linq==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ruponentModel;
public class Person
{
public int Age { get; set; }
public string Name { get; set; }
List<Person> friends = new List<Person>();
public List<Person> Friends
{
get { return friends; }
}
public Person()
{
}
public Person(string name)
{
Name = name;
}
}
class Projection
{
static void Main()
{
List<Person> family = new List<Person>
{
new Person {Name="H", Age=31},
new Person {Name="J", Age=31},
new Person {Name="T", Age=4},
new Person {Name="W", Age=1}
};
var converted = family.ConvertAll(delegate(Person person)
{ return new { person.Name, IsAdult = (person.Age >= 18) }; }
);
foreach (var person in converted)
{
Console.WriteLine("{0} is an adult? {1}",
person.Name, person.IsAdult);
}
}
}</source>

==Projection Operators: do calculation in select statement==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
int[] numbers = { 5, 4, 1, 3, 9};
var numsPlusOne =
from n in numbers
select n + 1;
Console.WriteLine("Numbers + 1:");
foreach (var i in numsPlusOne) {
Console.WriteLine(i);
}
}
}</source>

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в 15:31, 26 мая 2010

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