本主题中的示例演示如何使用 OrderBy
和 OrderByDescending
方法使用查询表达式语法查询 AdventureWorks Sales Model 。 这些示例中使用的 AdventureWorks 销售模型基于 AdventureWorks 示例数据库中的 Contact、Address、Product、SalesOrderHeader 和 SalesOrderDetail 表生成。
本主题中的示例使用以下 using
/Imports
语句:
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
示例:
以下示例用于 OrderBy 返回按姓氏排序的联系人列表。
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
示例:
以下示例用于 OrderBy 按姓氏长度对联系人列表进行排序。
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
示例:
以下示例使用 orderby… descending
(Order By … Descending
在 Visual Basic 中),该方法等效 OrderByDescending 于该方法,以从高到低对价目表进行排序。
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
示例:
以下示例使用 OrderBy 并 ThenBy 返回按姓氏排序的联系人列表,然后按名字排序。
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
示例:
以下示例使用 OrderBy… Descending
与该方法等效 ThenByDescending 的方法对产品列表进行排序,首先按名称排序,然后按从高到低的标价排序。
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: {product.ProductID} Product Name: {product.Name} List Price {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