System.Threading.Tasks.Parallel.For Method

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.

Syntax

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

Parameters

fromInclusive
The start index, inclusive.
toExclusive
The end index, exclusive.
body
The delegate that is invoked once per iteration.

Returns

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

Remarks

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 (long), and a System.Threading.Tasks.ParallelLoopState instance that may be used to break out of the loop prematurely.

Calling the ParallelLoopState.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 ParallelLoopState.Stop method instead of using ParallelLoopState.Break. Calling ParallelLoopState.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 ParallelLoopState.Break, there are no guarantees regarding which other iterations will not execute.

If a loop is ended prematurely, the System.Threading.Tasks.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.

Requirements

Namespace: System.Threading.Tasks
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 4.0.0.0