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Enumerable.LongCount<TSource> Method (IEnumerable<TSource>)

.NET Framework 4.5

Returns an Int64 that represents the total number of elements in a sequence.

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

public static long LongCount<TSource>(
	this IEnumerable<TSource> source
)

Type Parameters

TSource: The type of the elements of source.

Parameters

source: Type: System.Collections.Generic.IEnumerable<TSource>
An IEnumerable<T> that contains the elements to be counted.

Return Value

Type: System.Int64
The number of elements 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).

Exceptions

Exception	Condition
ArgumentNullException	source is null.
OverflowException	The number of elements exceeds MaxValue.

Remarks

Use this method rather than Count when you expect the result to be greater than MaxValue.

In Visual Basic query expression syntax, an Aggregate Into LongCount() clause translates to an invocation of LongCount.

Examples

The following code example demonstrates how to use LongCount<TSource>(IEnumerable<TSource>) to count the elements in an array.

            string[] fruits = { "apple", "banana", "mango", 
                                  "orange", "passionfruit", "grape" };

            long count = fruits.LongCount();

            Console.WriteLine("There are {0} fruits in the collection.", count);

            /*
             This code produces the following output:

             There are 6 fruits in the collection.
            */

Version Information

.NET Framework

Supported in: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Platforms

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Reference

Enumerable Class

LongCount Overload

System.Linq Namespace

Other Resources

Aggregate Clause (Visual Basic)

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