IOrderedEnumerable<TElement>.CreateOrderedEnumerable<TKey> Method (Func<TElement, TKey>, IComparer<TKey>, Boolean)

 

Performs a subsequent ordering on the elements of an IOrderedEnumerable<TElement> according to a key.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

IOrderedEnumerable<TElement> CreateOrderedEnumerable<TKey>(
	Func<TElement, TKey> keySelector,
	IComparer<TKey> comparer,
	bool descending
)

Parameters

keySelector
Type: System.Func<TElement, TKey>

The Func<T, TResult> used to extract the key for each element.

comparer
Type: System.Collections.Generic.IComparer<TKey>

The IComparer<T> used to compare keys for placement in the returned sequence.

descending
Type: System.Boolean

true to sort the elements in descending order; false to sort the elements in ascending order.

Return Value

Type: System.Linq.IOrderedEnumerable<TElement>

An IOrderedEnumerable<TElement> whose elements are sorted according to a key.

Type Parameters

TKey

The type of the key produced by keySelector.

The functionality provided by this method is like that provided by ThenBy or ThenByDescending, depending on whether descending is true or false. They both perform a subordinate ordering of an already sorted sequence of type IOrderedEnumerable<TElement>.

The following code example demonstrates how to use CreateOrderedEnumerable<TKey> to perform a secondary ordering on an IOrderedEnumerable<TElement>.

// Create an array of strings to sort.
string[] fruits = { "apricot", "orange", "banana", "mango", "apple", "grape", "strawberry" };
// First sort the strings by their length.
IOrderedEnumerable<string> sortedFruits2 =
    fruits.OrderBy(fruit => fruit.Length);
// Secondarily sort the strings alphabetically, using the default comparer.
IOrderedEnumerable<string> sortedFruits3 =
    sortedFruits2.CreateOrderedEnumerable<string>(
        fruit => fruit,
        Comparer<string>.Default, false);

// Output the resulting sequence of strings.
foreach (string fruit in sortedFruits3)
    Console.WriteLine(fruit);

// This code produces the following output:
//
// apple
// grape
// mango
// banana
// orange
// apricot
// strawberry

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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