Sorgu İfadesi Söz Dizimi Örnekleri: Sıralama (LINQ to DataSet)
Bu konudaki örneklerde, sorgu ifadesi söz dizimini OrderBykullanarak sonuçları DataSet sorgulamak ve sıralamak için , OrderByDescending, Reverseve ThenByDescending yöntemlerinin nasıl kullanılacağı gösterilmektedir.
FillDataSet Bu örneklerde kullanılan yöntem, DataSet'e Veri Yükleme bölümünde belirtilmiştir.
Bu konudaki örneklerde AdventureWorks örnek veritabanındaki Contact, Address, Product, SalesOrderHeader ve SalesOrderDetail tabloları kullanılmıştır.
Bu konudaki örneklerde aşağıdaki using/Imports deyimler kullanılır:
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Globalization;
using System.Linq;
using System.Windows.Forms;
Option Explicit On
Imports System.Linq
Imports System.Linq.Expressions
Imports System.Collections.Generic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.Common
Imports System.Globalization
Daha fazla bilgi için bkz . Nasıl yapılır: Visual Studio'da LINQ to DataSet Projesi Oluşturma.
OrderBy
Örnek
Bu örnek, soyadına göre sıralanmış kişilerin listesini döndürmek için kullanır OrderBy .
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable contacts = ds.Tables["Contact"];
IEnumerable<DataRow> query =
from contact in contacts.AsEnumerable()
orderby contact.Field<string>("LastName")
select contact;
Console.WriteLine("The sorted list of last names:");
foreach (DataRow contact in query)
{
Console.WriteLine(contact.Field<string>("LastName"));
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim contacts As DataTable = ds.Tables("Contact")
Dim query = _
From contact In contacts.AsEnumerable() _
Select contact _
Order By contact.Field(Of String)("LastName")
Console.WriteLine("The sorted list of last names:")
For Each contact In query
Console.WriteLine(contact.Field(Of String)("LastName"))
Next
Örnek
Bu örnek, kişi listesini soyadı uzunluğuna göre sıralamak için kullanır OrderBy .
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable contacts = ds.Tables["Contact"];
IEnumerable<DataRow> query =
from contact in contacts.AsEnumerable()
orderby contact.Field<string>("LastName").Length
select contact;
Console.WriteLine("The sorted list of last names (by length):");
foreach (DataRow contact in query)
{
Console.WriteLine(contact.Field<string>("LastName"));
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim contacts As DataTable = ds.Tables("Contact")
Dim query = _
From contact In contacts.AsEnumerable() _
Select contact _
Order By contact.Field(Of String)("LastName").Length
Console.WriteLine("The sorted list of last names (by length):")
For Each contact In query
Console.WriteLine(contact.Field(Of String)("LastName"))
Next
Orderbydescending
Örnek
Bu örnekte, fiyat listesini en yüksekten en düşüğe OrderByDescending sıralamak için yöntemine eşdeğer olan ()Order By … Descending kullanılır orderby… descending .
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable products = ds.Tables["Product"];
IEnumerable<Decimal> query =
from product in products.AsEnumerable()
orderby product.Field<Decimal>("ListPrice") descending
select product.Field<Decimal>("ListPrice");
Console.WriteLine("The list price from highest to lowest:");
foreach (Decimal product in query)
{
Console.WriteLine(product);
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim products As DataTable = ds.Tables("Product")
Dim query = _
From product In products.AsEnumerable() _
Select product _
Order By product.Field(Of Decimal)("ListPrice") Descending
Console.WriteLine("The list price From highest to lowest:")
For Each product In query
Console.WriteLine(product.Field(Of Decimal)("ListPrice"))
Next
Ters kaydet
Örnek
Bu örnek, 20 Şubat 2002'den önceki siparişlerin OrderDate listesini oluşturmak için kullanırReverse.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable orders = ds.Tables["SalesOrderHeader"];
IEnumerable<DataRow> query = (
from order in orders.AsEnumerable()
where order.Field<DateTime>("OrderDate") < new DateTime(2002, 02, 20)
select order).Reverse();
Console.WriteLine("A backwards list of orders where OrderDate < Feb 20, 2002");
foreach (DataRow order in query)
{
Console.WriteLine(order.Field<DateTime>("OrderDate"));
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim orders As DataTable = ds.Tables("SalesOrderHeader")
Dim query = ( _
From order In orders.AsEnumerable() _
Where order.Field(Of DateTime)("OrderDate") < New DateTime(2002, 2, 20) _
Select order).Reverse()
Console.WriteLine("A backwards list of orders where OrderDate < Feb 20, 2002")
For Each order In query
Console.WriteLine(order.Field(Of DateTime)("OrderDate"))
Next
Thenbydescending
Örnek
Bu örnekte OrderBy… Descending , bir ürün listesini ada ve ardından liste fiyatına ThenByDescending göre en yüksekten en düşüğe göre sıralamak için yöntemiyle eşdeğer olan kullanılır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable products = ds.Tables["Product"];
IEnumerable<DataRow> query =
from product in products.AsEnumerable()
orderby product.Field<string>("Name"),
product.Field<Decimal>("ListPrice") descending
select product;
foreach (DataRow product in query)
{
Console.WriteLine("Product ID: {0} Product Name: {1} List Price {2}",
product.Field<int>("ProductID"),
product.Field<string>("Name"),
product.Field<Decimal>("ListPrice"));
}
' Fill the DataSet.
Dim ds As New DataSet()
ds.Locale = CultureInfo.InvariantCulture
' See the FillDataSet method in the Loading Data Into a DataSet topic.
FillDataSet(ds)
Dim products As DataTable = ds.Tables("Product")
Dim query = _
From product In products.AsEnumerable() _
Order By product.Field(Of String)("Name"), _
product.Field(Of Decimal)("ListPrice") Descending _
Select product
For Each product In query
Console.Write("Product ID: " & product.Field(Of Integer)("ProductID"))
Console.Write(" Product Name: " & product.Field(Of String)("Name"))
Console.WriteLine(" List Price: " & product.Field(Of Decimal)("ListPrice"))
Next