Enumerable.LongCount<TSource> Method (IEnumerable<TSource>)
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Returns an Int64 that represents the total number of elements in a sequence.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function LongCount(Of TSource) ( _
source As IEnumerable(Of TSource) _
) As Long
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 nulla null reference (Nothing in Visual Basic). |
| 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.
' Create an array of strings.
Dim fruits() As String = _
{"apple", "banana", "mango", "orange", "passionfruit", "grape"}
' Get the number of items in the array.
Dim count As Long = fruits.LongCount()
' Display the result.
outputBlock.Text &= "There are " & count & " fruits in the collection." & vbCrLf
' This code produces the following output:
'
' There are 6 fruits in the collection.
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.
*/
Version Information
Silverlight
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
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.