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

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

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

Syntax

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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.

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.

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      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.
      */