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Exemples de syntaxe d'expression de requête : classement

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Les exemples de cette rubrique montrent comment utiliser les méthodes OrderBy et OrderByDescending pour interroger le modèle de vente AdventureWorks à l’aide de la syntaxe d’expression de requête. Le modèle de vente AdventureWorks Sales Model utilisé dans ces exemples est construit à partir des tables Contact, Address, Product, SalesOrderHeader et SalesOrderDetail de l'exemple de base de données AdventureWorks.

Les exemples de cette rubrique utilisent les instructions using/Imports suivantes :

using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Objects;
using System.Globalization;
using System.Data.EntityClient;
using System.Data.SqlClient;
using System.Data.Common;


Option Explicit On
Option Strict On
Imports System.Data.Objects
Imports System.Globalization

OrderBy

Exemple

L'exemple suivant utilise OrderBy pour retourner une liste de contacts classés par nom de famille.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Contact> sortedNames =
        from n in context.Contacts
        orderby n.LastName
        select n;

    Console.WriteLine("The sorted list of last names:");
    foreach (Contact n in sortedNames)
    {
        Console.WriteLine(n.LastName);
    }
}

Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts

    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

Exemple

L'exemple suivant utilise OrderBy pour trier une liste de contacts par longueur du nom de famille.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Contact> sortedNames =
        from n in context.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);
    }
}

Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts

    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

OrderByDescending

Exemple

L'exemple suivant utilise orderby… descending (Order By … Descending en Visual Basic), qui est l'équivalent de la méthode OrderByDescending, pour trier la liste de prix du plus élevé au plus bas.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Decimal> sortedPrices =
        from p in context.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);
    }
}

Using context As New AdventureWorksEntities
    Dim products As ObjectSet(Of Product) = context.Products

    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

ThenBy

Exemple

L'exemple suivant utilise OrderBy et ThenBy pour retourner une liste de contacts classée par nom de famille, puis par prénom.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Contact> sortedContacts =
        from contact in context.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);
    }
}

Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts

    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

ThenByDescending

Exemple

L'exemple suivant utilise OrderBy… Descending, qui est l'équivalent de la méthode ThenByDescending, pour trier une liste de produits, d'abord par nom, puis par prix, du plus élevé au plus bas.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Product> query =
        from product in context.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);
    }
}

Using context As New AdventureWorksEntities
    Dim products As ObjectSet(Of Product) = context.Products

    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

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