Enumerable.ElementAtOrDefault<TSource> Method

Returns the element at a specified index in a sequence or a default value if the index is out of range.

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

public static TSource ElementAtOrDefault<TSource>(
	this IEnumerable<TSource> source,
	int index
)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable<TSource>
An IEnumerable<T> to return an element from.
index
Type: System.Int32
The zero-based index of the element to retrieve.

Return Value

Type: TSource
default(TSource) if the index is outside the bounds of the source sequence; otherwise, the element at the specified position in the source sequence.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is null.

If the type of source implements IList<T>, that implementation is used to obtain the element at the specified index. Otherwise, this method obtains the specified element.

The default value for reference and nullable types is null.

The following code example demonstrates how to use ElementAtOrDefault<TSource>. This example uses an index that is outside the bounds of the array.


            string[] names =
                { "Hartono, Tommy", "Adams, Terry", "Andersen, Henriette Thaulow",
                    "Hedlund, Magnus", "Ito, Shu" };

            int index = 20;

            string name = names.ElementAtOrDefault(index);

            Console.WriteLine(
                "The name chosen at index {0} is '{1}'.",
                index,
                String.IsNullOrEmpty(name) ? "<no name at this index>" : name);

            /*
             This code produces the following output:

             The name chosen at index 20 is '<no name at this index>'.
            */



.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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