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Parallel.For Method (Int64, Int64, Action<Int64, ParallelLoopState>)

Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel and the state of the loop can be monitored and manipulated.

Namespace:  System.Threading.Tasks
Assembly:  mscorlib (in mscorlib.dll)

public static ParallelLoopResult For(
	long fromInclusive,
	long toExclusive,
	Action<long, ParallelLoopState> body
)

Parameters

fromInclusive
Type: System.Int64
The start index, inclusive.
toExclusive
Type: System.Int64
The end index, exclusive.
body
Type: System.Action<Int64, ParallelLoopState>
The delegate that is invoked once per iteration.

Return Value

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

ExceptionCondition
ArgumentNullException

The body argument is null.

AggregateException

The exception that contains all the individual exceptions thrown on all threads.

The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). It is provided with the following parameters: the iteration count (Int64), and a ParallelLoopState instance that may be used to break out of the loop prematurely.

Calling the Break method informs the for operation that iterations after the current one don’t have to be executed, but all iterations before the current one do.

Therefore, calling Break is similar to using a break operation within a conventional for loop in a language like C#, but it is not a perfect substitute: For example, there is no guarantee that iterations after the current one will definitely not execute.

If executing all iterations before the current one is not necessary, use the Stop method instead of using Break. Calling Stop informs the for loop that it may abandon all remaining iterations, regardless of whether they're before or after the current iteration, because all required work will have already been completed. However, as with Break, there are no guarantees regarding which other iterations will not execute.

If a loop is ended prematurely, the ParallelLoopResult structure that is returned will contain relevant information about the loop's completion.

If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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