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Sorgu İfadesi Söz Dizimi Örnekleri: Kısıtlama (LINQ to DataSet)

Bu konudaki örnekler, sorgu ifadesi söz dizimini kullanarak Where yöntemini DataSet sorgulamak için nasıl kullanacağınızı göstermektedir.

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 deyimleri kullanılır:

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Globalization;
using System.Linq;
using System.Windows.Forms;

Daha fazla bilgi için bkz. Nasıl yapılır: Visual Studio'da LINQ to DataSet Projesi Oluşturma.

Nerede

Örnek

Bu örnek tüm çevrimiçi siparişleri döndürür.

// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);

DataTable orders = ds.Tables["SalesOrderHeader"];

var query =
    from order in orders.AsEnumerable()
    where order.Field<bool>("OnlineOrderFlag") == true
    select new
    {
        SalesOrderID = order.Field<int>("SalesOrderID"),
        OrderDate = order.Field<DateTime>("OrderDate"),
        SalesOrderNumber = order.Field<string>("SalesOrderNumber")
    };

foreach (var onlineOrder in query)
{
    Console.WriteLine($"Order ID: {onlineOrder.SalesOrderID} Order date: {onlineOrder.OrderDate:d} Order number: {onlineOrder.SalesOrderNumber}");
}

' 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 Boolean)("OnlineOrderFlag") = True _
    Select New With { _
        .SalesOrderID = order.Field(Of Integer)("SalesOrderID"), _
        .OrderDate = order.Field(Of DateTime)("OrderDate"), _
        .SalesOrderNumber = order.Field(Of String)("SalesOrderNumber") _
     }

For Each onlineOrder In query
    Console.Write("Order ID: " & onlineOrder.SalesOrderID)
    Console.Write(" Order date: " & onlineOrder.OrderDate)
    Console.WriteLine(" Order number: " & onlineOrder.SalesOrderNumber)
Next

Örnek

Bu örnek, sipariş miktarının 2'den büyük ve 6'dan küçük olduğu siparişleri döndürür.

// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);

DataTable orders = ds.Tables["SalesOrderDetail"];

var query =
    from order in orders.AsEnumerable()
    where order.Field<Int16>("OrderQty") > 2 &&
        order.Field<Int16>("OrderQty") < 6
    select new
    {
        SalesOrderID = (int)order.Field<int>("SalesOrderID"),
        OrderQty = order.Field<Int16>("OrderQty")
    };

foreach (var order in query)
{
    Console.WriteLine($"Order ID: {order.SalesOrderID} Order quantity: {order.OrderQty}");
}

' 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("SalesOrderDetail")

Dim query = _
    From order In orders.AsEnumerable() _
    Where order.Field(Of Short)("OrderQty") > 2 And _
            order.Field(Of Short)("OrderQty") < 6 _
    Select New With _
    { _
        .SalesOrderID = order.Field(Of Integer)("SalesOrderID"), _
        .OrderQty = order.Field(Of Short)("OrderQty") _
    }

For Each order In query
    Console.Write("Order ID: " & order.SalesOrderID)
    Console.WriteLine(" Order quantity: " & order.OrderQty)
Next

Örnek

Bu örnek tüm kırmızı renkli ürünleri döndürür.

// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);

DataTable products = ds.Tables["Product"];

var query =
    from product in products.AsEnumerable()
    where product.Field<string>("Color") == "Red"
    select new
    {
        Name = product.Field<string>("Name"),
        ProductNumber = product.Field<string>("ProductNumber"),
        ListPrice = product.Field<Decimal>("ListPrice")
    };

foreach (var product in query)
{
    Console.WriteLine($"Name: {product.Name}");
    Console.WriteLine($"Product number: {product.ProductNumber}");
    Console.WriteLine($"List price: ${product.ListPrice}");
    Console.WriteLine("");
}

' 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() _
    Where product.Field(Of String)("Color") = "Red" _
    Select New With _
       { _
           .Name = product.Field(Of String)("Name"), _
           .ProductNumber = product.Field(Of String)("ProductNumber"), _
           .ListPrice = product.Field(Of Decimal)("ListPrice") _
       }

For Each product In query
    Console.WriteLine("Name: " & product.Name)
    Console.WriteLine("Product number: " & product.ProductNumber)
    Console.WriteLine("List price: $ " & product.ListPrice & vbNewLine)
Next

Örnek

Bu örnek, 1 Aralık 2002'den sonra yapılan siparişleri bulmak için Where yöntemini ve ardından her siparişin ayrıntılarını almak için GetChildRows yöntemini kullanır.

// 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, 12, 1)
    select order;

Console.WriteLine("Orders that were made after 12/1/2002:");
foreach (DataRow order in query)
{
    Console.WriteLine($"OrderID {order.Field<int>("SalesOrderID")} Order date: {order.Field<DateTime>("OrderDate"):d} ");
    foreach (DataRow orderDetail in order.GetChildRows("SalesOrderHeaderDetail"))
    {
        Console.WriteLine($"  Product ID: {orderDetail["ProductID"]} Unit Price {orderDetail["UnitPrice"]}");
    }
}

' 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 As IEnumerable(Of DataRow) = _
    From order In orders.AsEnumerable() _
    Where order.Field(Of DateTime)("OrderDate") >= New DateTime(2002, 12, 1) _
    Select order

Console.WriteLine("Orders that were made after 12/1/2002:")
For Each order As DataRow In query
    Console.WriteLine("OrderID {0} Order date: {1:d} ", _
        order.Field(Of Integer)("SalesOrderID"), order.Field(Of DateTime)("OrderDate"))
    For Each orderDetail As DataRow In order.GetChildRows("SalesOrderHeaderDetail")
        Console.WriteLine("  Product ID: {0} Unit Price {1}", _
            orderDetail("ProductID"), orderDetail("UnitPrice"))
    Next
Next

Ayrıca bkz.

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