Exemplos de Queries Linq

Exemplos de Queries utilizando o Linq

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Xml.Linq;

public partial class _Default : System.Web.UI.Page

NorthwindDataContext db = new NorthwindDataContext();

protected void Page_Load(object sender, EventArgs e)

protected void lstOption_SelectedIndexChanged(object sender, EventArgs e)

lblQuery.Text = String.Empty;

lblLinq.Text = String.Empty;

private void SelectLinq()

string strOption = lstOption.SelectedValue;

switch (strOption)

case "Hello":

break;

case "Products":

break;

case "Combine":

break;

case "Where":

break;

case "XML":

break;

default:

break;

private void Hello()

string[] greetings = { "hello world", "hello LINQ", "hello ASPNETi" };

//Coleção

IEnumerable<string> q = from s in greetings

where s.EndsWith("LINQ")

select s;

lblLinq.Text = "string[] greetings = { \"hello world\", \"hello LINQ\", \"hello ASPNETi\" };";

lblQuery.Text = "IEnumerable&lt;string&gt; q = from s in greetings <br> where s.EndsWith(\"LINQ\") <br> select s";

private void Combine()

// Combine Where() and Select() for common queries

IQueryable<string> q = db.Customers.Where(c => c.City == "London").Select(c => c.ContactName);

string strLinq = "Queryable&lt;string&gt; q = db.Customers.Where(c => c.City == \"London\").Select(c => c.ContactName);";

private void Products()

IQueryable<Product> q = from p in db.Products

where p.Category.CategoryName == "Beverages"

select p;

string strLinq = "IQueryable&lt;Product&gt; q = from p in db.Products <br> where p.Category.CategoryName == \"Beverages\" <br>select p;";

private void Where()

IQueryable<Product> q = from p in db.Products

where p.UnitsInStock == 0

select p;

string strLinq = "IQueryable&lt;Product&gt; q = from p in db.Products where p.UnitsInStock == 0 select p;";

private void XML()

XElement books = XElement.Parse(

@"<books>

</books>");

var q =

from book in books.Elements("book")

where (string)book.Element("author") == "Joe Rattz"

select new { Title = book.Element("title").Value, Author = book.Element("author").Value };

lblQuery.Text = "var q = <br> from book in books.Elements(\"book\") <br> where (string)book.Element(\"author\") == \"Joe Rattz\" <br> select new { Title = book.Element(\"title\").Value, Author = book.Element(\"author\").Value };";