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Parallel.ForEach<TSource> Method (Partitioner<TSource>, Action<TSource, ParallelLoopState>)

.NET Framework 4.6 and 4.5

Executes a foreach (For Each in Visual Basic) operation on a System.Collections.Concurrent.Partitioner in which iterations may run in parallel, and the state of the loop can be monitored and manipulated.

Namespace:  System.Threading.Tasks
Assemblies:   mscorlib (in mscorlib.dll)
  System.Threading.Tasks.Parallel (in System.Threading.Tasks.Parallel.dll)

public static ParallelLoopResult ForEach<TSource>(
	Partitioner<TSource> source,
	Action<TSource, ParallelLoopState> body
)

Type Parameters

TSource

The type of the elements in source.

Parameters

source
Type: System.Collections.Concurrent.Partitioner<TSource>

The partitioner that contains the original data source.

body
Type: System.Action<TSource, ParallelLoopState>

The delegate that is invoked once per iteration.

Return Value

Type: System.Threading.Tasks.ParallelLoopResult
A structure that contains information about which portion of the loop completed.

ExceptionCondition
ArgumentNullException

The source argument is null.

-or-

The body argument is null.

InvalidOperationException

The SupportsDynamicPartitions property in the source partitioner returns false.

-or-

A method in the source partitioner returns null.

-or-

The GetPartitions method in the source partitioner does not return the correct number of partitions.

This overload is provided for scenarios where you want to override the default partitioning scheme. For example, small loop bodies might benefit from partitioning the range. The Parallel.ForEach method expects custom partitioners to support dynamic partitioning. For more information, see Custom Partitioners for PLINQ and TPL and How to: Implement Dynamic Partitions.

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

.NET for Windows Phone apps

Supported in: Windows Phone 8.1

Portable Class Library

Supported in: Portable Class Library
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