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ParallelEnumerable.Count<TSource> Method (ParallelQuery<TSource>, Func<TSource, Boolean>)

.NET Framework (current version)

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Returns a number that represents how many elements in the specified parallel sequence satisfy a condition.

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

public static int Count<TSource>(
	this ParallelQuery<TSource> source,
	Func<TSource, bool> predicate


Type: System.Linq.ParallelQuery<TSource>

A sequence that contains elements to be counted.

Type: System.Func<TSource, Boolean>

A function to test each element for a condition.

Return Value

Type: System.Int32

A number that represents how many elements in the sequence satisfy the condition in the predicate function.

Type Parameters


The type of the elements of source.

Exception Condition

The query was canceled with the token passed in through WithCancellation.


source or predicate is a null reference (Nothing in Visual Basic).


The number of elements in source is larger than MaxValue. (In this case the InnerException is OverflowException) -or- One or more exceptions occurred during the evaluation of the query.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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