Sorgu İfadesi Söz Dizimi Örnekleri: Bölümleme (LINQ to DataSet)
Bu konudaki örneklerde, sorgu ifadesi söz dizimini Skip kullanarak sorgulamak DataSet için ve Take 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.
Atla
Örnek
Bu örnek, Seattle'daki Skip ilk iki adres dışında tümünü almak için yöntemini kullanır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable addresses = ds.Tables["Address"];
DataTable orders = ds.Tables["SalesOrderHeader"];
var query = (
from address in addresses.AsEnumerable()
from order in orders.AsEnumerable()
where address.Field<int>("AddressID") == order.Field<int>("BillToAddressID")
&& address.Field<string>("City") == "Seattle"
select new
{
City = address.Field<string>("City"),
OrderID = order.Field<int>("SalesOrderID"),
OrderDate = order.Field<DateTime>("OrderDate")
}).Skip(2);
Console.WriteLine("All but first 2 orders in Seattle:");
foreach (var order in query)
{
Console.WriteLine("City: {0} Order ID: {1} Total Due: {2:d}",
order.City, order.OrderID, order.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 addresses As DataTable = ds.Tables("Address")
Dim orders As DataTable = ds.Tables("SalesOrderHeader")
Dim query = ( _
From address In addresses.AsEnumerable() _
From order In orders.AsEnumerable() _
Where (address.Field(Of Integer)("AddressID") = _
order.Field(Of Integer)("BillToAddressID")) _
And address.Field(Of String)("City") = "Seattle" _
Select New With _
{ _
.City = address.Field(Of String)("City"), _
.OrderID = order.Field(Of Integer)("SalesOrderID"), _
.OrderDate = order.Field(Of DateTime)("OrderDate") _
}).Skip(2)
Console.WriteLine("All but first 2 orders in Seattle:")
For Each addOrder In query
Console.Write("City: " & addOrder.City)
Console.Write(" Order ID: " & addOrder.OrderID)
Console.WriteLine(" Order date: " & addOrder.OrderDate)
Next
Take
Örnek
Bu örnek, Seattle'daki Take ilk üç adresi almak için yöntemini kullanır.
// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);
DataTable addresses = ds.Tables["Address"];
DataTable orders = ds.Tables["SalesOrderHeader"];
var query = (
from address in addresses.AsEnumerable()
from order in orders.AsEnumerable()
where address.Field<int>("AddressID") == order.Field<int>("BillToAddressID")
&& address.Field<string>("City") == "Seattle"
select new
{
City = address.Field<string>("City"),
OrderID = order.Field<int>("SalesOrderID"),
OrderDate = order.Field<DateTime>("OrderDate")
}).Take(3);
Console.WriteLine("First 3 orders in Seattle:");
foreach (var order in query)
{
Console.WriteLine("City: {0} Order ID: {1} Total Due: {2:d}",
order.City, order.OrderID, order.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 addresses As DataTable = ds.Tables("Address")
Dim orders As DataTable = ds.Tables("SalesOrderHeader")
Dim query = ( _
From address In addresses.AsEnumerable() _
From order In orders.AsEnumerable() _
Where (address.Field(Of Integer)("AddressID") = _
order.Field(Of Integer)("BillToAddressID")) _
And address.Field(Of String)("City") = "Seattle" _
Select New With _
{ _
.City = address.Field(Of String)("City"), _
.OrderID = order.Field(Of Integer)("SalesOrderID"), _
.OrderDate = order.Field(Of DateTime)("OrderDate") _
}).Take(3)
Console.WriteLine("First 3 orders in Seattle:")
For Each order In query
Console.Write("City: " & order.City)
Console.Write(" Order ID: " & order.OrderID)
Console.WriteLine(" Order date: " & order.OrderDate)
Next