Ejemplos de sintaxis de expresión de consultas: ordenación (LINQ to Entities)
Los ejemplos de este tema muestran cómo se utilizan los métodos OrderBy y OrderByDescending para consultar el modelo AdventureWorks Sales con la sintaxis de las expresiones de consulta. El modelo AdventureWorks Sales que se usa en estos ejemplos se crea a partir de las tablas Contact, Address, Product, SalesOrderHeader y SalesOrderDetail en la base de datos de ejemplo de AdventureWorks.
Los ejemplos de este tema usan las siguientes instrucciones using/Imports:
Option Explicit On
Option Strict On
Imports L2EExamplesVB.AdventureWorksModel
Imports System.Data.Objects
Imports System.Globalization
using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Objects;
using AdventureWorksModel;
using System.Globalization;
Para obtener más información, vea Cómo crear un proyecto de LINQ to Entities en Visual Studio.
OrderBy
Ejemplo
En el ejemplo siguiente se utiliza OrderBy para devolver una lista de contactos organizados por apellido.
Using AWEntities As New AdventureWorksEntities
Dim contacts As ObjectQuery(Of Contact) = AWEntities.Contact
Dim sortedContacts = _
From contact In contacts _
Order By contact.LastName _
Select contact
Console.WriteLine("The sorted list of last names:")
For Each n As Contact In sortedContacts
Console.WriteLine(n.LastName)
Next
End Using
using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
ObjectQuery<Contact> contacts = AWEntities.Contact;
IQueryable<Contact> sortedNames =
from n in contacts
orderby n.LastName
select n;
Console.WriteLine("The sorted list of last names:");
foreach (Contact n in sortedNames)
{
Console.WriteLine(n.LastName);
}
}
Ejemplo
En el ejemplo siguiente se utiliza OrderBy para ordenar una lista de contactos por longitud del apellido.
Using AWEntities As New AdventureWorksEntities
Dim contacts As ObjectQuery(Of Contact) = AWEntities.Contact
Dim sortedNames = _
From n In contacts _
Order By n.LastName.Length _
Select n
Console.WriteLine("The sorted list of last names (by length):")
For Each n As Contact In sortedNames
Console.WriteLine(n.LastName)
Next
End Using
using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
ObjectQuery<Contact> contacts = AWEntities.Contact;
IQueryable<Contact> sortedNames =
from n in contacts
orderby n.LastName.Length
select n;
Console.WriteLine("The sorted list of last names (by length):");
foreach (Contact n in sortedNames)
{
Console.WriteLine(n.LastName);
}
}
OrderByDescending
Ejemplo
En el ejemplo siguiente se utiliza orderby… descending (Order By … Descending) en Visual Basic, que es equivalente al método OrderByDescending, para ordenar el precio de venta de mayor a menor.
Using AWEntities As New AdventureWorksEntities
Dim products As ObjectQuery(Of Product) = AWEntities.Product
Dim sortedPrices = _
From product In products _
Order By product.ListPrice Descending _
Select product.ListPrice
Console.WriteLine("The list price from highest to lowest:")
For Each price As Decimal In sortedPrices
Console.WriteLine(price)
Next
End Using
using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
ObjectQuery<Product> products = AWEntities.Product;
IQueryable<Decimal> sortedPrices =
from p in products
orderby p.ListPrice descending
select p.ListPrice;
Console.WriteLine("The list price from highest to lowest:");
foreach (Decimal price in sortedPrices)
{
Console.WriteLine(price);
}
}
ThenBy
Ejemplo
En el ejemplo siguiente se utiliza OrderBy y ThenBy para devolver una lista de contactos ordenados por apellido y luego por nombre.
Using AWEntities As New AdventureWorksEntities
Dim contacts As ObjectQuery(Of Contact) = AWEntities.Contact
Dim sortedContacts = _
From contact In contacts _
Order By contact.LastName, contact.FirstName _
Select contact
Console.WriteLine("The list of contacts sorted by last name then by first name:")
For Each sortedContact As Contact In sortedContacts
Console.WriteLine(sortedContact.LastName + ", " + sortedContact.FirstName)
Next
End Using
using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
ObjectQuery<Contact> contacts = AWEntities.Contact;
IQueryable<Contact> sortedContacts =
from contact in contacts
orderby contact.LastName, contact.FirstName
select contact;
Console.WriteLine("The list of contacts sorted by last name then by first name:");
foreach (Contact sortedContact in sortedContacts)
{
Console.WriteLine(sortedContact.LastName + ", " + sortedContact.FirstName);
}
}
ThenByDescending
Ejemplo
En el ejemplo siguiente se utiliza OrderBy… Descending, que es equivalente al método ThenByDescending, para ordenar una lista de productos, primero por nombre y después por precio de venta, de mayor a menor.
Using AWEntities As New AdventureWorksEntities
Dim products As ObjectQuery(Of Product) = AWEntities.Product
Dim query As IQueryable(Of Product) = _
From product In products _
Order By product.Name, product.ListPrice Descending _
Select product
For Each prod As Product In query
Console.WriteLine("Product ID: {0} Product Name: {1} List Price {2}", _
prod.ProductID, _
prod.Name, _
prod.ListPrice)
Next
End Using
using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
ObjectQuery<Product> products = AWEntities.Product;
IQueryable<Product> query =
from product in products
orderby product.Name, product.ListPrice descending
select product;
foreach (Product product in query)
{
Console.WriteLine("Product ID: {0} Product Name: {1} List Price {2}",
product.ProductID,
product.Name,
product.ListPrice);
}
}
Vea también
Conceptos
Ejemplos de sintaxis de expresión de consultas (LINQ to Entities)