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


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: 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.

Type Parameters


The type of the elements of source.

Exception Condition

source is null.


The number of elements exceeds MaxValue.

Use this method rather than Count<TSource> 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<TSource>.

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.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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