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ParallelEnumerable.WithDegreeOfParallelism<TSource> Method (ParallelQuery<TSource>, Int32)

.NET Framework (current version)

Sets the degree of parallelism to use in a query. Degree of parallelism is the maximum number of concurrently executing tasks that will be used to process the query.

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

public static ParallelQuery<TSource> WithDegreeOfParallelism<TSource>(
	this ParallelQuery<TSource> source,
	int degreeOfParallelism


Type: System.Linq.ParallelQuery<TSource>

A ParallelQuery on which to set the limit on the degrees of parallelism.

Type: System.Int32

The degree of parallelism for the query. The default value is Math.Min(ProcessorCount, MAX_SUPPORTED_DOP) where MAX_SUPPORTED_DOP is 512.

Return Value

Type: System.Linq.ParallelQuery<TSource>

ParallelQuery representing the same query as source, with the limit on the degrees of parallelism set.

Type Parameters


The type of elements of source.

Exception Condition

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


degreeOfParallelism is less than 1 or greater than 511.


WithDegreeOfParallelism is used multiple times in 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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