LongCount(TSource) Method (IEnumerable(TSource))

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 Parameters


The type of the elements of 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.


source is null.


The number of elements exceeds MaxValue.

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.

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();

      outputBlock.Text += String.Format("There are {0} fruits in the collection.", count) + "\n";

       This code produces the following output:

       There are 6 fruits in the collection.


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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